Data Sheet

July 2002

T7690 5.0 V T1/E1 Quad Line Interface

T7693 3.3 V T1/E1 Quad Line Interface

1 Features

Four fully integrated T1/E1 line interfaces

Includes all driver, receiver, equalization, clock recovery,
and jitter attenuation functions

Ultralow power consumption

Robust operation for increased system margin

High interference immunity

On-chip transmit equalization for improved sensitivity

Low-impedance drivers for reduced power consumption

Selectable transmit or receive jitter attenuation/clock
smoothing

3-state transmit drivers

High-speed microprocessor interface

Automatic transmit monitor function

Per-channel powerdown

For use in systems that are compliant with AT&T

CB119; TR-TSY-000170, TR-TSY-000009, TR-TSY-
000499, TR-TSY-000253; ANSI

T1.102 and T1.403;

ITU-T G.703, G.732, G.735-9, G.775, G.823-4, and I.431

Common transformer for transmit/receive

Fine-pitch (25 mil spacing) surface-mount package, 100-
pin bumpered quad flat pack

40 °C to +85 °C operating temperature range

2 Applications

SONET/SDH multiplexers

Asynchronous multiplexers (M13)

Digital access cross connects (DACs)

Channel banks

Digital radio base stations, remote wireless
modules

PBX interfaces

3 Overview

The T7690 and T7693 are fully integrated quad line inter-
faces containing four transmit and receive channels for use
in both North American (T1/DS1) and European (E1/CEPT)
applications. The devices have many of the same functions
as the Agere T7290A and provide additional flexibility for
the system designer.

Included is a parallel microprocessor interface that allows
the user to define the architecture, initiate loopbacks, and
monitor alarms. The interface is compatible with many
commercially available microprocessors.

The receiver performs clock and data recovery using a fully
integrated digital phase-locked loop. This digital implemen-
tation prevents false lock conditions that are common when
recovering sparse data patterns with analog phase-locked
loops. Equalization circuitry in the receiver guarantees a
high level of interference immunity. As an option, the raw
sliced data (no retiming) can be output on the receive data
pins.

Transmit equalization is implemented with low-impedance
output drivers that provide shaped waveforms to the trans-
former, guaranteeing template conformance. The quad
device will interface to the digital cross connect (DSX) at
lengths of up to 655 ft. for DS1 operation, or to line imped-
ances of 75

or 120

for CEPT operation.

A selectable jitter attenuator may be placed in the receive
signal path for low-bandwidth, line-synchronous applica-
tions, or it may be placed in the transmit path for multi-
plexer applications where DS1/CEPT signals are
demultiplexed from higher rate signals. The jitter attenuator
will perform the clock smoothing required on the resulting
demultiplexed gapped clock.

Table of Contents

Contents

Page

Contents

Page

Agere Systems Inc.

Data Sheet

July 2002

T7693 3.3 V T1/E1 Quad Line Interface

T7690 5.0 V T1/E1 Quad Line Interface

1 Features ........................................................................ 1
2 Applications ................................................................... 1
3 Overview ........................................................................ 1
4 Single Channel Block Diagram ...................................... 4
5 Pin Information ............................................................. 5

5.1 System Interface Pin Options ................................. 9

6 Receiver ...................................................................... 11

6.1 Data Recovery ...................................................... 11
6.2 Jitter ...................................................................... 11
6.3 Receiver Configuration Modes ............................. 11

6.3.1 Clock/Data Recovery Mode (CDR) ............. 11
6.3.2 Zero Substitution Decoding (CODE) ........... 11
6.3.3 Alternate Logic Mode (ALM) ....................... 11
6.3.4 Alternate Clock Mode (ACM) ...................... 11
6.3.5 Loss Shutdown (LOSSD) ............................ 12

6.4 Receiver Alarms ................................................... 12

6.4.1 Analog Loss-of-Signal (ALOS) Alarm .......... 12
6.4.2 Digital Loss-of-Signal (DLOS) Alarm ........... 12
6.4.3 Bipolar Violation (BPV) Alarm ..................... 12

6.5 DS1 Receiver Specifications ................................ 13
6.6 CEPT Receiver Specifications .............................. 14

7 Transmitter .................................................................. 15

7.1 Output Pulse Generation ...................................... 15
7.2 Jitter ...................................................................... 15
7.3 Transmitter Configuration Modes ......................... 16

7.3.1 Zero Substitution

Encoding/Decoding (CODE) ....................... 16

7.3.2 All Ones (AIS, Blue Signal)

Generator (TBS) .......................................... 16

7.4 Transmitter Alarms ............................................... 16

7.4.1 Loss-of-Transmit Clock (LOTC) Alarm ........ 16
7.4.2 Transmit Driver Monitor (TDM) Alarm ......... 16

7.5 DS1 Transmitter Pulse Template

and Specifications ................................................ 16

7.6 CEPT Transmitter Pulse Template

and Specifications ................................................ 17

8 Jitter Attenuator ........................................................... 19

8.1 Data Delay ............................................................ 19
8.2 Generated (Intrinsic) Jitter .................................... 19
8.3 Jitter Transfer Function ......................................... 19
8.4 Jitter Tolerance ..................................................... 19
8.5 Jitter Attenuator Enable ........................................ 19

8.5.1 Jitter Attenuator Receive

Path Enable (JAR) ...................................... 19

8.5.2 Jitter Attenuator Transmit

Path Enable (JAT) ....................................... 20

8.6 Loopbacks ............................................................ 20

8.6.1 Full Local Loopback (FLLOOP) ................... 20
8.6.2 Remote Loopback (RLOOP) ....................... 20
8.6.3 Digital Local Loopback (DLLOOP) .............. 20

8.7 Other Features ..................................................... 20

8.7.1 Powerdown (PWRDN) ................................ 20

8.7.2 RESET (

5(6(7

, SWRESET) .......................20

8.8 Loss of XCLK Reference Clock (LOXC) ...............21
8.9 In-Circuit Testing and Driver 3-State (ICT) ............21

9 Microprocessor Interface ..............................................22

9.1 Overview ...............................................................22
9.2 Microprocessor Configuration Modes ...................22
9.3 Microprocessor Interface Pinout Definitions ..........23
9.4 Microprocessor Clock (MPCLK) Specifications .....24
9.5 Internal Chip Select Function ................................24
9.6 Microprocessor Interface Register Architecture ....24

9.6.1 Alarm Register Overview (0000, 0001) ........26
9.6.2 Alarm Mask Register Overview

(0010, 0011) ................................................26

9.6.3 Global Control Register Overview

(0100, 0101) ................................................27

9.6.4 Channel Configuration Register Overview

(0110--1001) ...............................................27

9.6.5 Other Registers ............................................28

10 Timing Characteristics ................................................29

10.1 I/O Timing ...........................................................29
10.2 Interface Data Timing .........................................34

10.2.1 Logic Interface Characteristics .................35

10.3 XCLK Reference Clock .......................................35

11 Electrical Characteristics ............................................36

11.1 Power Supply Bypassing ....................................36
11.2 Power Specifications ...........................................36
11.3 Absolute Maximum Ratings ................................37
11.4 Handling Precautions ..........................................37
11.5 Operating Conditions ..........................................37

12 External Line Termination Circuitry ............................38

12.1 T7690 .................................................................38
12.2 T7693 .................................................................39

13 Outline Diagram .........................................................40

13.1 100-Pin BQFP ....................................................40

Figures

Page

Figure 4-1. Block Diagram (Single Channel)......................4
Figure 5-1. Pin Diagram .....................................................5
Figure 7-1. DSX-1 Isolated Pulse Template.....................17
Figure 7-2. ITU-T G.703 Pulse Template.........................17
Figure 10-1. Mode 1--Read Cycle Timing

(MPMODE = 0, MPMUX = 0).......................30

Figure 10-2. Mode 1--Write Cycle Timing

(MPMODE = 0, MPMUX = 0).......................30

Figure 10-3. Mode 2--Read Cycle Timing

(MPMODE = 0, MPMUX = 1).......................31

Figure 10-4. Mode 2--Write Cycle Timing

(MPMODE = 0, MPMUX = 1).......................31

Figure 10-5. Mode 3--Read Cycle Timing

(MPMODE = 1, MPMUX = 0).......................32

Agere Systems Inc.

Data Sheet

July 2002

T7693 3.3 V T1/E1 Quad Line Interface

T7690 5.0 V T1/E1 Quad Line Interface

Table of Contents

(continued)

Figure

Page

Figure

Page

Figure 10-6. Mode 3--Write Cycle Timing

(MPMODE = 1, MPMUX = 0) ...................... 32

Figure 10-7. Mode 4--Read Cycle Timing

(MPMODE = 1, MPMUX = 1) ...................... 33

Figure 10-8. Mode 4--Write Cycle Timing

(MPMODE = 1, MPMUX = 1) ...................... 33

Table

Page

Table 5-1. Pin Descriptions................................................ 6
Table 5-2. Pin Mapping.................................................... 10
Table 6-1. Digital Loss-of-Signal Standard Select ........... 12
Table 6-2. DS1 Receiver Specifications .......................... 13
Table 6-3. CEPT Receiver Specifications........................ 14
Table 7-1. Equalizer/Rate Control.................................... 15
Table 7-2. DSX-1 Pulse Template Corner Points

(From CB119) ................................................. 17

Table 7-3. DS1 Transmitter Specifications....................... 17
Table 7-4. CEPT Transmitter Specifications .................... 18
Table 8-1. List of Low-Bandwidth Jitter

Specification Documents ................................ 19

Table 8-2. Loopback Control............................................ 20
Table 9-1. Microprocessor Configuration Modes ............. 22
Table 9-2. MODE [1--4] Microprocessor

Pin Definitions................................................. 23

Table 9-3. Microprocessor Input Clock Specifications ..... 24
Table 9-4. Register Set .................................................... 25

Figure 10-9. Interface Data Timing (ACM = 0) .................34
Figure 12-1. T7690 External Line Termination Circuitry ..38
Figure 12-2. T7693 External Line Termination Circuitry ..39

Table

Page

Table 9-5. Alarm Registers...............................................26
Table 9-6. Alarm Mask Registers .....................................26
Table 9-7. Global Control Register (0100)........................27
Table 9-8. Global Control Register (0101)........................27
Table 9-9. Channel Configuration Registers ....................28
Table 10-1. Microprocessor Interface I/O Timing

Specifications.................................................29

Table 10-2. Interface Data Timing ....................................34
Table 10-3. Logic Interface Characteristics ......................35
Table 10-4. XCLK Timing Specifications ..........................35
Table 11-1. Power Specifications .....................................36
Table 11-2. Absolute Maximum Ratings...........................37
Table 11-3. Handling Precaution ......................................37
Table 11-4. Recommended Operating Conditions ...........37
Table 12-1. Termination Components by Application .......38
Table 12-2. Termination Components by Application .......39

T7690 5.0 V T1/E1 Quad Line Interface

Data Sheet

T7693 3.3 V T1/E1 Quad Line Interface

July 2002

5 Pin Information

(continued)

6
6

Agere Systems Inc.

Table 5-1. Pin Descriptions

Pin

Symbol

Type*

Name/Description

1, 51

GND

Ground Reference for Substrate.

2, 6

GNDX1

Ground Reference for Line Drivers.

46, 50

GNDX2

52, 56

GNDX3

96, 100

GNDX4

TTIP1

Transmit Bipolar Tip. Positive bipolar transmit output data to the analog line inter-
face.

TTIP2

TTIP3

TTIP4

Power Supply for Line Drivers. The T7690 device requires a 5 V ± 5% power sup-
ply on these pins. The T7693 device requires a 3.3 V ± 5% power supply on these
pins.

TRING1

Transmit Bipolar Ring. Negative bipolar transmit output data to the analog line
interface.

TRING2

TRING3

TRING4

DDA

Power Supply for Analog Circuitry. The T7690 device requires a 5 V ± 5% power
supply on these pins. The T7693 device requires a 3.3 V ± 5% power supply on
these pins.

DDA

RTIP1

Receive Bipolar Tip. Positive bipolar receive input data from the analog line inter-
face.

RTIP2

RTIP3

RTIP4

RRING1

Receive Bipolar Ring. Negative bipolar receive input data from the analog line
interface.

RRING2

RRING3

RRING4

GND

Ground Reference for Analog Circuitry.

GND

Ground Reference for Digital Circuitry.

GND

* P = power, I = input, O = output, and Iu

= input with internal pull-up.

Data Sheet

T7690 5.0 V T1/E1 Quad Line Interface

July 2002

T7693 3.3 V T1/E1 Quad Line Interface

5 Pin Information

(continued)

Agere Systems Inc.

DDD

Power Supply for Digital Circuitry. The T7690 device requires a 5 V ± 5% power
supply on these pins. The T7693 device requires a 3.3 V ± 5% power supply on
these pins.

DDD

RND1/BPV1

Receive Negative Data. When in dual-rail (DUAL = 1: register 5, bit 4) clock recov-
ery mode (CDR = 1: register 5, bit 0), this signal is the receive negative NRZ output
data to the terminal equipment. When in data slicing mode (CDR = 0), this signal is
the raw sliced negative output data of the front end.

Bipolar Violation. When in single-rail (DUAL = 0: register 5, bit 4) clock recovery
mode (CDR = 1: register 5, bit 0), and CODE = 1 (register 5, bit 3), this signal is
asserted high to indicate the occurrence of a code violation in the receive data
stream. If CODE = 0, this signal is asserted to indicate the occurrence of a bipolar
violation in the receive data system.

RND2/BPV2

RND3/BPV3

RND4/BPV4

RPD1/

RDATA1

Receive Positive Data. When in dual-rail (DUAL = 1: register 5, bit 4) clock recov-
ery mode (CDR = 1: register 5, bit 0), this signal is the receive positive NRZ output
data to the terminal equipment. When in data slicing mode (CDR = 0), this signal is
the raw sliced positive output data of the front end.

Receive Data. When in single-rail (DUAL = 0: register 5, bit 4) clock recovery mode
(CDR = 1: register 5, bit 0), this signal is the receive NRZ output data.

RPD2/

RDATA2

RPD3/

RDATA3

RPD4/

RDATA4

RCLK1/

ALOS1

Receive Clock. In clock recovery mode (CDR = 1: register 5, bit 0), this signal is the
receive clock for the terminal equipment. The duty cycle of RCLK is 50% ± 5%.

Analog Loss-of-Signal. In data slicing mode (CDR = 0: register 5, bit 0), this signal
is asserted high to indicate low-amplitude receive data at the RTIP/RRING inputs.

RCLK2/

ALOS2

RCLK3/

ALOS3

RCLK4/

ALOS4

TND1

Transmit Negative Data. Transmit negative NRZ input data from the terminal
equipment.

TND2

TND3

TND4

TPD1/TDATA1

Transmit Positive Data. When in dual-rail mode (DUAL = 1: register 5, bit 4), this
signal is the transmit positive NRZ input data from the terminal equipment.

Transmit Data. When in single-rail mode (DUAL = 0: register 5, bit 4), this signal is
the transmit NRZ input data from the terminal equipment.

TPD2/TDATA2

TPD3/TDATA3

TPD4/TDATA4

TCLK1

Transmit Clock. DS1 (1.544 MHz ± 32 ppm) or CEPT (2.048 MHz ± 50 ppm) clock
signal from the terminal equipment.

TCLK2

TCLK3

TCLK4

Table 5-1. Pin Descriptions (continued)

Pin

Symbol

Type*

Name/Description

* P = power, I = input, O = output, and Iu

= input with internal pull-up.

T7690 5.0 V T1/E1 Quad Line Interface

Data Sheet

T7693 3.3 V T1/E1 Quad Line Interface

July 2002

5 Pin Information

(continued)

8
8

Agere Systems Inc.

WR_DS

Write (Active-Low). If MPMODE = 1 (pin 21), this pin is asserted low by the micro-
processor to initiate a write cycle.

Data Strobe (Active-Low). If MPMODE = 0 (pin 21), this pin becomes the data
strobe for the microprocessor. When R/W = 0 (write), a low applied to this pin
latches the signal on the data bus into internal registers.

MPMUX

Microprocessor Multiplex Mode. Setting MPMUX = 1 allows the microprocessor
interface to accept multiplexed address and data signals. Setting MPMUX = 0
allows the microprocessor interface to accept demultiplexed (separate) address and
data signals.

MPMODE

Microprocessor Mode. When MPMODE = 1, the device uses the address latch
enable type microprocessor read/write protocol with separate read and write con-
trols. Setting MPMODE = 0 allows the device to use the address strobe type micro-
processor read/write protocol with a separate data strobe and a combined read/
write control.

RD_R/W

Read (Active-Low). If MPMODE = 1 (pin 21), this pin is asserted low by the micro-
processor to initiate a read cycle.

Read/Write. If MPMODE = 0, this pin is asserted high by the microprocessor to indi-
cate a read cycle or asserted low to indicate a write cycle.

ALE_AS

Address Latch Enable. If MPMODE = 1 (pin 21), this pin becomes the address
latch enable for the microprocessor. When this pin transitions from high to low, the
address bus inputs are latched into the internal registers.

Address Strobe (Active-Low). If MPMODE = 0, this pin becomes the address
strobe for the microprocessor. When this pin transitions from high to low, the
address bus inputs are latched into the internal registers.

Chip Select (Active-Low). This pin is asserted low by the microprocessor to enable
the microprocessor interface. If MPMUX = 1 (pin 20), CS can be externally tied low
to use the internal chip selection function (see

Section 9.5

). An internal 100 k

pull-

up is on this pin.

INT

Interrupt. This pin is asserted high to indicate an interrupt produced by an alarm
condition in register 0 or 1. The activation of this pin can be masked by microproces-
sor registers 2, 3, and 4.

RDY_DTACK

Ready. If MPMODE = 1 (pin 21), this pin is asserted high to indicate the device has
completed a read or write operation. This pin is in a 3-state condition when CS (pin
24) is high.

Data Transfer Acknowledge (Active-Low). If MPMODE = 0, this pin is asserted
low to indicate the device has completed a read or write operation.

27, 78

GND

Ground Reference for Microprocessor Interface and Control Circuitry.

28, 77

DDC

Power Supply for Microprocessor Interface and Control Circuitry. The T7690
device requires a 5 V ± 5% power supply on these pins. The T7693 device requires
a 3.3 V ± 5% power supply on these pins.

XCLK

Reference Clock. A valid reference clock (24.704 MHz ± 100 ppm for DS1 opera-
tion, 32.768 MHz ± 100 ppm for CEPT operation) must be provided at this input for
certain applications (see

Section 10.3

). XCLK must be an independent, continu-

ously active, ungapped, and unjittered clock to guarantee device performance spec-
ifications. An internal 100 k

pull-up is on this pin.

Table 5-1. Pin Descriptions (continued)

Pin

Symbol

Type*

Name/Description

* P = power, I = input, O = output, and Iu

= input with internal pull-up.

Data Sheet

T7690 5.0 V T1/E1 Quad Line Interface

July 2002

T7693 3.3 V T1/E1 Quad Line Interface

5 Pin Information

(continued)

Agere Systems Inc.

5.1 System Interface Pin Options

The system interface can be configured to operate in a number of different modes, as shown in

Table 5-2

. Dual-rail or sin-

gle-rail operation is possible using the DUAL control bit (register 5, bit 4). Dual-rail mode is enabled when DUAL = 1; single-
rail mode is enabled when DUAL = 0. In dual-rail operation, data received from the line interface on RTIP and RRING
appears on RPD (pins 14, 38, 64, and 88) and RND (pins 13, 39, 63, and 89) at the system interface and data transmitted
from the system interface on TPD (pins 17, 35, 67, and 85) and TND (pins 16, 36, 66, and 86) appears on TTIP and TRING
at the line interface. In single-rail operation, data received from the line interface on RTIP and RRING appears on RDATA
(pins 14, 38, 64, 88) at the system interface and data transmitted from the system interface on TDATA (pins 17, 35, 67, and
85) appears on TTIP and TRING at the line interface.

In both dual-rail and single-rail operation, the clock/data recovery mode is selectable via the CDR bit (register 5, bit 0).
When CDR = 1, the clock and data recovery is enabled and the system interface operates in a nonreturn-to-zero (NRZ) dig-
ital format. When CDR = 0, the clock and data recovery is disabled and the system interface operates on unretimed sliced
data in RZ data format (see

Section 6.1

BCLK

Blue Clock. Input clock signal used to transmit the blue signal (alarm indication sig-
nal (AIS) all 1s data pattern). In DS1 mode, this clock is 1.544 MHz ± 32 ppm, and in
CEPT mode, this clock is 2.048 MHz ± 50 ppm. An internal 100 k

pull-up is on this

pin.

LOXC

Loss-of-XCLK. This pin is asserted high when the XCLK signal (pin 29) is not
present.

RESET

Hardware Reset (Active-Low). If RESET is forced low, all internal states in the line
interface paths are reset and data flow through each channel will be momentarily
disrupted (see the RESET (RESET, SWRESET) section). The RESET pin must be
held low for a minimum of 10 µs. An internal 50 k

pull-up is on this pin.

ICT

In-Circuit Test Control (Active-Low). If ICT is forced low, certain output pins are
placed in a high-impedance state (see the In-Circuit Testing and Driver 3-State (ICT)
section). An internal 50 k

pull-up is on this pin.

AD7

I/O

Microprocessor Interface Address/Data Bus. If MPMUX = 0 (pin 20), these pins
become the bidirectional, 3-statable data bus. If MPMUX = 1, these pins become
the multiplexed address/data bus. In this mode, only the lower 4 bits (AD[3:0]) are
used for the internal register addresses.

AD6

AD5

AD4

AD3

AD2

AD1

AD0

Microprocessor Interface Address. If MPMUX = 0 (pin 20), these pins become
the address bus for the microprocessor interface registers.

If MPMUX = 1, A3 (pin 79) can be externally tied high to use the internal chip selec-
tion function (see

Section 9.5

). If this function is not used, A[3:0] must be externally

tied low.

MPCLK

Microprocessor Interface Clock. Microprocessor interface clock rates from twice
the frequency of the line clock (3.088 MHz for DS1 operation, 4.096 MHz for CEPT
operation) to 16.384 MHz are supported.

Table 5-1. Pin Descriptions (continued)

Pin

Symbol

Type*

Name/Description

* P = power, I = input, O = output, and Iu

= input with internal pull-up.

Agere Systems Inc.

Data Sheet

T7690 5.0 V T1/E1 Quad Line Interface

July 2002

T7693 3.3 V T1/E1 Quad Line Interface

6 Receiver

6.1 Data Recovery

The receive line interface transmission format of the device
is bipolar alternate mark inversion (AMI). It accepts input
data with a frequency tolerance of ±130 ppm (DS1) or
±80 ppm (CEPT). The receiver first restores the incoming
data and detects analog loss-of-signal. Subsequent pro-
cessing is optional and depends on the programmable
device configuration established within the microprocessor
interface registers. The receiver operates with high interfer-
ence immunity, utilizing an equalizer to restore fast rise/fall
times following maximum cable loss. The signal is then
peak-detected and sliced to produce digital representations
of the data.

Selectable clock recovery of the sliced data, digital loss-of-
signal, jitter attenuation, and data decoding are performed.
For applications bypassing the clock recovery function
(CDR = 0), the receive digital output format is unretimed
sliced data (RZ positive and negative data). For clock
recovery applications (CDR = 1), the receive digital output
format is nonreturn to zero (NRZ) with selectable dual-rail
or single-rail system interface. The recovered clock (RCLK,
pins 15, 37, 65, and 87) is only provided when CDR = 1
(see

Table 5-2

Timing recovery is performed by a digital phase-locked
loop that uses XCLK (pin 29) as a reference to lock to the
incoming data. Because the reference clock is a multiple of
the received data rate, the output RCLK (pins 15, 37, 65,
and 87) will always be a valid DS1/CEPT clock that elimi-
nates false-lock conditions. During periods with no input
signal, the free-run frequency is defined to be XCLK/16.
RCLK is always active with a duty-cycle centered at 50%,
deviating by no more than ±5%. Valid data is recovered
within the first few bit periods after the application of XCLK.
The delay of the data through the receive circuitry is
approximately 1 to 14 bit periods, depending on the CDR
and CODE configurations. Additional delay is introduced if
the jitter attenuator is selected for operation in the receive
path (see

Section 8.1

6.2 Jitter

The receiver is designed to accommodate large amounts of
input jitter. The receiver jitter performance far exceeds the
requirements shown in

Table 6-2

and

Table 6-3

. Jitter

transfer is independent of input ones density on the line
interface.

6.3 Receiver Configuration Modes

6.3.1 Clock/Data Recovery Mode (CDR)

The clock/data recovery function in the receive path is
selectable via the CDR bit (register 5, bit 0). If CDR = 1, the
clock and data recovery function is enabled and provides a
recovered clock (RCLK) with retimed data (RPD/RDATA,
RND). If CDR = 0, the clock and data recovery function is
disabled, and the RZ data from the slicers is provided over
RPD and RND to the system. In this mode, ALOS is avail-
able on the RCLK/ALOS pins, and downstream functions
selected by microprocessor register 5 (JAR, ACM, LOSSD)
are ignored.

6.3.2 Zero Substitution Decoding (CODE)

When single-rail operation is selected with DUAL = 0 (reg-
ister 5, bit 4), the B8ZS/HDB3 zero substitution decoding
can be selected via the CODE bit (register 5, bit 3). If
CODE = 1, the B8ZS/HDB3 decoding function is enabled in
the receive path and decoded receive data and code viola-
tions appear on the RDATA and BPV pins, respectively. If
CODE = 0, receive data and any bipolar violations (such as
two consecutive 1s of the same polarity) appear on the
RDATA and BPV pins, respectively.

6.3.3 Alternate Logic Mode (ALM)

The alternate logic mode (ALM) control bit (register 5, bit 5)
selects the receive and transmit data polarity (i.e., active-
high vs. active-low). If ALM = 0, the receiver circuitry (and
transmit input) assumes the data to be active-low polarity. If
ALM = 1, the receiver circuitry (and transmit input)
assumes the data to be active-high polarity. The ALM con-
trol is used in conjunction with the ACM control (register 5,
bit 6) to determine the receive data retiming mode.

6.3.4 Alternate Clock Mode (ACM)

The alternate clock mode (ACM) control bit (register 5, bit
6) selects the positive or negative clock edge of the receive
clock (RCLK) for receive data retiming. The ACM control is
used in conjunction with ALM (register 5, bit 5) control to
determine the receive data retiming modes. If ACM = 1, the
receive data is retimed on the positive edge of the receive
clock. If ACM = 0, the receive data is retimed on the nega-
tive edge of the receive clock.

Note: This control does not affect the timing relationship

for the transmitter inputs.

T7690 5.0 V T1/E1 Quad Line Interface

Data Sheet

T7693 3.3 V T1/E1 Quad Line Interface

July 2002

6 Receiver

(continued)

Agere Systems Inc.

6.3.5 Loss Shutdown (LOSSD)

The loss shutdown (LOSSD) control bit (register 5, bit 7)
places the digital receiver outputs (RPD, RND) in a prede-
termined state when a digital loss-of-signal (DLOS) alarm
occurs in register 0 and 1, bits 1 and 5. If LOSSD = 1, the
RPD and RND outputs are forced to their inactive states
(selected by ALM) and the receive clock (RCLK) free runs
during a DLOS alarm condition. If LOSSD = 0, the RPD,
RND, and RCLK outputs will remain unaffected during the
DLOS alarm condition.

6.4 Receiver Alarms

6.4.1 Analog Loss-of-Signal (ALOS) Alarm

An analog loss-of-signal (ALOS) detector monitors the
incoming signal amplitude and reports its status to the
alarm registers 0 and 1. During DS1 and CEPT modes of
operation, analog loss-of-signal is indicated (ALOS = 1) if
the amplitude at the receive input drops below a voltage
that is 17 dB below the nominal pulse amplitude. The slicer
outputs are clamped to the inactive state and the clock
recovery will provide a free-running RCLK when ALOS = 1.
The alarm circuitry also provides 4 dB of hysteresis to elim-
inate ALOS chattering. The time required to detect ALOS is
between 1 ms and 2.6 ms and is timed by the blue clock
(see

Section 7.3.2

). Detection time is independent of signal

amplitude before the loss condition occurs.

6.4.2 Digital Loss-of-Signal (DLOS) Alarm

A digital loss-of-signal (DLOS) detector guarantees the
quality of the signal as defined in standards documents,
and reports its status to the alarm registers 0 and 1. During
DS1 operation, digital loss-of-signal (DLOS = 1) is indi-
cated if 100 or more consecutive 0s occur in the receive
data stream.

The DLOS indication is deactivated when the average ones
density of at least 12.5% is received in 100 contiguous
pulse positions. During CEPT operation, DLOS is indicated
when 255 or more consecutive 0s occur in the receive data
stream. The DLOS indication is deactivated when the aver-
age ones density of at least 12.5% is received in 255 con-
tiguous pulse positions. The LOSSTD control bit (register
4, bit 2) selects the conformance protocols for DLOS per
Table 6-1. TR-TSY-000009 adds the additional constraint
of no more than 15 consecutive 0s when determining the
12.5% 1s density.

6.4.3 Bipolar Violation (BPV) Alarm

The bipolar violation (BPV) alarm is used only in single-rail
mode of operation of the device (see

Section 5.1

). When

B8ZS(DS1)/HDB3(CEPT) coding is not used
(i.e., CODE = 0), any violations in the receive data (such as
two or more consecutive 1s on a rail) are indicated on the
RND/BPV pins. When B8ZS(DS1)/HDB3(CEPT) coding is
used (i.e., CODE = 1), the HDB3/B8ZS code violations are
reflected on the RND/BPV pins.

Table 6-1. Digital Loss-of-Signal Standard Select

LOSSTD

DS1 Mode

CEPT Mode

T1M1.3/93-005

ITU-T G.775

TR-TSY-000009

ITU-T G.775

Data Sheet

T7690 5.0 V T1/E1 Quad Line Interface

July 2002

T7693 3.3 V T1/E1 Quad Line Interface

6 Receiver

(continued)

Agere Systems Inc.

6.5 DS1 Receiver Specifications

During DS1 operation, the receiver will perform as specified in Table 6-2

* Below the nominal pulse amplitude of 3.0 V using Agere transformers:

2745G3 for T7690 and components with values in

Figure 12-1

and

Table 12-1

2664AL for T7693 and components with values in

Figure 12-2

and

Table 12-2

Amount of cable loss.
Using Agere transformers:

2745G3 for T7690 and components with values in

Figure 12-1

and

Table 12-1

2664AL for T7693 and components with values in

Figure 12-2

and

Table 12-2

Table 6-2. DS1 Receiver Specifications

Parameter

Min

Typ

Max

Unit

Specification

Analog Loss-of-Signal:

Threshold
Hysteresis

--
--

dB*

--
--

Maximum Sensitivity

Jitter Transfer:

3 dB Bandwidth, Single-pole Rolloff
Peaking

--
--

3.84

0.1

kHz

TR-TSY-000499
TR-TSY-000499

Generated Jitter

0.032

0.04

p-p

TR-TSY-000499,

ITU-T G.824

Jitter Tolerance

ITU-T G.823-4,

TR-TSY-000009,
TR-TSY-000499,

TR-TSY-000170

Return Loss

51 kHz to 102 kHz
102 kHz to 1.544 MHz
1.544 MHz to 2.316 MHz

14
20
16

--
--
--

dB
dB
dB

--
--
--

Digital Loss-of-Signal:

Flag Asserted, Consecutive Bit Posi-

tions

Flag Deasserted

Data Density
Maximum Consecutive

Zeros

100

12.5

--
--

--
--
--

15
99

zeros

% ones

zeros
zeros

TR-TSY-000009

ITU-T G.775,

T1M1.3/93-005

T7690 5.0 V T1/E1 Quad Line Interface

Data Sheet

T7693 3.3 V T1/E1 Quad Line Interface

July 2002

6 Receiver

(continued)

Agere Systems Inc.

6.6 CEPT Receiver Specifications

During CEPT operation, the receiver will perform as specified in Table 6-3.

* Below the nominal pulse amplitude of 3.0 V for 120

and 2.37 V for 75

applications using Agere transformers:

2745CA for T7690 (CEPT 75

option 2 and CEPT 120

applications) and components with values in

Figure 12-1

and

Table 12-1

2664AJ for T7693 (CEPT 75

option 2 and CEPT 120

applications) and components with values in

Figure 12-2

and

Table 12-2

2745AJ2 for T7690 (CEPT 75

option 1) and components with values in

Figure 12-1

and

Table 12-1

2664AK for T7693 (CEPT 75

option 1) and components with values in

Figure 12-2

and

Table 12-2

Amount of cable loss allowed when a 18 dB asynchronous interference signal is added with the desired signal source.
Using Agere transformers:

2745CA for T7690 (CEPT 75

option 2 and CEPT 120

applications) and components with values in

Figure 12-1

and

Table 12-1

2664AJ for T7693 (CEPT 75

option 2 and CEPT 120

applications) and components with values in

Figure 12-2

and

Table 12-2

2745AJ2 for T7690 (CEPT 75

option 1) and components with values in

Figure 12-1

and

Table 12-1

2664AK for T7693 (CEPT 75

option 1) and components with values in

Figure 12-2

and

Table 12-2

Table 6-3. CEPT Receiver Specifications

Parameter

Min

Typ

Max

Unit

Specification

Analog Loss-of-Signal:

Threshold
Hysteresis

--
--

dB*

ITU-T G.775

ETSI 300 233:1992

Maximum Sensitivity

13.5

ITU-T G.703

Jitter Transfer:

3 dB Bandwidth, Single-pole Rolloff
Peaking

--
--

5.1

0.5

kHz

ITU-T G.735-9

Generated Jitter

0.032

0.04

p-p

ITU-T G.823, I.431

Jitter Tolerance

ITU-T G.823, I.431

Return Loss

51 kHz to 102 kHz
102 kHz to 2.048 MHz
2.048 MHz to 3.072 MHz

14
20
16

--
--
--

dB
dB
dB

ITU-T G.703

Digital Loss-of-Signal:

Flag Asserted, Consecutive Bit Posi-
tions
Flag Deasserted

255

12.5

zeros

% ones

ITU-T G.775

Agere Systems Inc.

Data Sheet

T7690 5.0 V T1/E1 Quad Line Interface

July 2002

T7693 3.3 V T1/E1 Quad Line Interface

7 Transmitter

7.1 Output Pulse Generation

The transmitter accepts a clock with NRZ data in single-rail mode (DUAL = 0: register 5, bit 4) or positive and negative NRZ
data in dual-rail mode (DUAL = 1) from the system. The device converts this data to a balanced bipolar signal (AMI format)
with optional B8ZS(DS1)/HDB3(CEPT) encoding and jitter attenuation. Low-impedance output drivers produce these
pulses on the line interface. Positive 1s are output as a positive pulse on TTIP, and negative 1s are output as a positive
pulse on TRING. Binary 0s are converted to null pulses. The total delay of the data from the system interface to the transmit
driver is approximately 3 to 11 bit periods, depending on the CODE (register 5, bit 3) configuration.

Additional delay results if the jitter attenuator is selected for use in the transmit path (see

Section 8.1

Transmit pulse shaping is controlled by the on-chip pulse-width controller and pulse equalizer. The pulse-width controller
produces the high-speed timing signals to accurately control the transmit pulse widths. This eliminates the need for a tightly
controlled transmit clock duty cycle that is usually required in discrete implementations. The pulse equalizer controls the
amplitudes of these pulse shapes. Different pulse equalizations are selected through proper settings of EQA, EQB, and
EQC (registers 6 to 9, bits 5 to 7) as described in Table 7-1.

* In DS1 mode, the distance to the DSX for 22-gauge PIC (ABAM) cable is specified. Use the maximum cable loss figures for other cable types. In CEPT

mode, equalization is specified for coaxial or twisted-pair cable.

Loss measured at 772 kHz.
In 75

applications, option 1 is recommended over option 2 for lower device power dissipation. Option 2 allows for the same transformer as used in

CEPT 120

applications.

7.2 Jitter

The intrinsic jitter of the transmit path, i.e., the jitter at TTIP/TRING when no jitter is applied to TCLK (and the jitter attenua-
tor is not selected, JAT = 0), is typically 5 ns

p-p

and will not exceed 0.02 UI

p-p

Table 7-1. Equalizer/Rate Control

EQA

EQB

EQC

Service

Clock Rate

Transmitter Equalization*

Maximum

Cable Loss

Feet

Meters

DS1

1.544 MHz

0 ft. to 131 ft.

0 m to 40 m

0.6

131 ft. to 262 ft.

40 m to 80 m

1.2

262 ft. to 393 ft.

80 m to 120 m

1.8

393 ft. to 524 ft.

120 m to 160 m

2.4

524 ft. to 655 ft.

160 m to 200 m

3.0

CEPT

2.048 MHz

(Option 2)

120

or 75

(Option 1)

Not Used

T7690 5.0 V T1/E1 Quad Line Interface

Data Sheet

T7693 3.3 V T1/E1 Quad Line Interface

July 2002

7 Transmitter

(continued)

Agere Systems Inc.

7.3 Transmitter Configuration Modes

7.3.1 Zero Substitution Encoding/Decoding (CODE)

Zero substitution encoding/decoding (B8ZS/HDB3) can be
activated only in the single-rail system interface mode
(DUAL = 0) by setting CODE = 1 (register 5, bit 3). Data
received from the line interface on RTIP and RRING will be
B8ZS/HDB3 decoded before appearing on RDATA (pins
14, 38, 64, 88) at the system interface. Likewise, data
transmitted from the system interface on TDATA (pins 17,
35, 67, 85) will be B8ZS/HDB3 encoded before appearing
on TTIP and TRING at the line interface. This mode also
allows coding violations, such as receiving two consecutive
1s of the same polarity from the line interface, to be output
on BPV (pins 13, 39, 63, and 89).

7.3.2 All Ones (AIS, Blue Signal) Generator (TBS)

When the transmit blue signal control is set (TBS = 1) for a
given channel (registers 6 to 9, bit 2), a continuous stream
of bipolar 1s is transmitted to the line interface (AIS). The
TPD/TDATA and TND inputs are ignored during this mode.
The TBS input is ignored when a remote loopback
(RLOOP) is selected using loopback control bits LOOPA
and LOOPB (registers 6 to 9, bits 3 and 4). (See

Section

8.6

To maintain application flexibility, the clock source used for
the blue signal is selected by configuring BCLK (pin 30). If
a data rate clock is input on the BCLK pin, it will be used to
transmit the blue signal. If BCLK = 0, then TCLK is used to
transmit the blue signal (the smoothed clock from the jitter
attenuator is used if JAT = 1 is selected). If BCLK = 1, then
XCLK (after being divided by a factor of 16) is used to
transmit the blue signal. After BCLK is established, a mini-
mum of 16 µs is required for the device to properly select
the clock. For any of the above options, the clock tolerance
must meet the normal line transmission rates (DS1
1.544 MHz ± 32 ppm; CEPT 2.048 MHz ± 50 ppm).

7.4 Transmitter Alarms

7.4.1 Loss-of-Transmit Clock (LOTC) Alarm

A loss-of-transmit clock alarm (LOTC = 1) is indicated if any
of the clocks in the transmit path disappear (registers 0 and
1, bits 3 and 7). This includes loss of TCLK input, loss of
RCLK during remote loopback, loss-of-jitter attenuator out-
put clock (when enabled), or the loss-of-clock from the
pulse-width controller.

For all of these conditions, a core transmitter timing clock is
lost and no data can be driven onto the line. Output drivers
TTIP and TRING are placed in a high-impedance state
when this alarm condition is active. The LOTC interrupt is
asserted between 3 µs and 16 µs after the clock disap-
pears, and deasserts immediately after detecting the first
clock edge.

7.4.2 Transmit Driver Monitor (TDM) Alarm

The transmit driver monitor detects two conditions: a non-
functional link due to faults on the primary of the transmit
transformer, and periods of no data transmission. The TDM
alarm (registers 0 and 1, bits 2 and 6) is the ORed function
of both faults and provides information about the integrity of
the transmit signal path.

The first monitoring function is provided to detect nonfunc-
tional links and protect the device from damage. The alarm
is set (TDM = 1) when one of the transmitter's line drivers
(TTIP or TRING) is shorted to power supply or ground, or
TTIP and TRING are shorted together. Under these condi-
tions, internal circuitry protects the device from damage
and excessive power supply current consumption by 3-stat-
ing the output drivers. The monitor detects faults on the
transformer primary, but transformer secondary faults may
not be detected. The monitor operates by comparing the
line pulses with the transmit inputs as in a bit error detect
mode. After 32 transmit clock cycles, the transmitter is
powered up in its normal operating mode. The drivers
attempt to correctly transmit the next data bit. If the error
persists, TDM remains active to eliminate alarm chatter
and the transmitter is internally protected for another 32
transmit clock cycles. This process is repeated until the
error condition is removed and the TDM alarm is deacti-
vated.

The second monitoring function is to indicate periods of no
data transmission. The alarm is set (TDM = 1) when 32
consecutive zeros have been transmitted and is cleared on
the detection of a single pulse. This alarm condition does
not alter the state or functionality of the signal path.

7.5 DS1 Transmitter Pulse Template and Specifi-

cations

The DS1 pulse shape template is specified at the DSX
(defined by CB119 and ANSI T1.102) and is illustrated in

Figure 7-1

. The device also meets the pulse template spec-

ified by ITU-T G.703 (not shown).

Data Sheet

T7690 5.0 V T1/E1 Quad Line Interface

July 2002

T7693 3.3 V T1/E1 Quad Line Interface

7 Transmitter

(continued)

Agere Systems Inc.

5-1160(C)r.6

Figure 7-1. DSX-1 Isolated Pulse Template

During DS1 operation, the transmitter tip/ring (TTIP/TRING
pins) will perform as specified in Table 7-3.

* Total power difference.

Measured in a 2 kHz band around the specified frequency.

Below the power at 772 kHz.

7.6 CEPT Transmitter Pulse Template and

Specifications

CEPT pulse shape template is specified at the system out-
put (defined by ITU-T G.703) and is shown in Figure 7-2.

5-3145(C)r.8

Figure 7-2. ITU-T G.703 Pulse Template

Table 7-2. DSX-1 Pulse Template Corner Points

(From CB119)

Maximum Curve

Minimum Curve

250
325
325
425
500
675
725

1100

1250

--
--

0.05
0.05
0.80
1.15
1.15
1.05
1.05

0.07

0.05
0.05

--
--

350
350
400
500
600
650
650
800
925

1100

1250

0.05
0.05

0.50
0.95
0.95
0.90
0.50

0.45
0.45
0.20
0.05
0.05

7,0( QV

/
,=('$

/
,
78'

(

Table 7-3. DS1 Transmitter Specifications

Parameter

Min

Typ Max Unit Specification

Output Pulse
Amplitude at
DSX*

2.5

2.8

3.5

AT&T CB119,

ANSI T1.102

Output Pulse
Width

338

350

362

Positive/Nega-
tive Pulse
Imbalance

0.1

0.4

Power Levels

772 kHz
1.544 MHz

12.6

17.9

dBm

120,1$/ 38/6(

T7690 5.0 V T1/E1 Quad Line Interface

Data Sheet

T7693 3.3 V T1/E1 Quad Line Interface

July 2002

7 Transmitter

(continued)

Agere Systems Inc.

During CEPT operation, the transmitter tip/ring (TTIP/TRING pins) will perform as specified in Table 7-4

* In accordance with the interfaces described in the

Section 11.3

and the

Section 11.4

, measured at the transformer secondary.

Using Agere transformers:

2745CA for T7690 (CEPT 75

option 2 and CEPT 120

applications) and components with values in

Figure 12-1

and

Table 12-1

2664AJ for T7693 (CEPT 75

option 2 and CEPT 120

applications) and components with values in

Figure 12-2

and

Table 12-2

2745AJ2 for T7690 (CEPT 75

option 1) and components with values in

Figure 12-1

and

Table 12-1

2664AK for T7693 (CEPT 75

option 1) and components with values in

Figure 12-2

and

Table 12-2.

Table 7-4. CEPT Transmitter Specifications

Parameter

Min

Typ

Max

Unit

Specification

Output Pulse Amplitude*:

120

2.13

2.7

2.37

3.0

2.61

3.3

V
V

ITU-T G.703

Output Pulse Width

232

244

256

Positive/Negative Pulse Imbalance:

Pulse Amplitude
Pulse Width

4
4

±1.5
±1.0

4
4

%
%

Zero Level (percentage of pulse amplitude)

Return Loss

51 kHz to 102 kHz
102 kHz to 2.048 MHz
2.048 MHz to 3.072 MHz

--
--
--

dB
dB
dB

CH-PTT

Agere Systems Inc.

Data Sheet

T7690 5.0 V T1/E1 Quad Line Interface

July 2002

T7693 3.3 V T1/E1 Quad Line Interface

8 Jitter Attenuator

The selectable jitter attenuator is provided for narrow-band-
width jitter transfer function applications. This selection is
done via control bits, which are global and affect all four
channels. One application is to provide narrow-bandwidth
jitter filtering for line-synchronization in the receive path.
Another use of the jitter attenuator is to provide clock
smoothing in the transmit signaling path for applications
such as synchronous/asynchronous demultiplexers. In
these applications, TCLK will have an instantaneous fre-
quency that is higher than the data rate and periods of
TCLK are suppressed (gapped) in order to set the average
long-term TCLK frequency to within the transmit line rate
specification.

The jitter attenuator does not degrade the jitter specifica-
tions of the receiver clock/data recovery circuit. In addition,
the jitter attenuator must meet the specifications for nar-
row-bandwidth applications as listed in Table 8-1.

8.1 Data Delay

Providing narrow-bandwidth jitter filtering requires data
buffering to increase the data delay through the jitter atten-
uator. The nominal data delay for the jitter attenuator is 33
bit periods, with a maximum data delay of 66 bit periods.
This delay is dependent on the input clock frequency,
XCLK frequency, input jitter, and gapped clock patterns.

8.2 Generated (Intrinsic) Jitter

Generated jitter is the amount of jitter appearing on the out-
put port when the applied input signal has no jitter. The jitter
attenuator of this device outputs a maximum of 0.04 UI
peak-to-peak intrinsic jitter.

8.3 Jitter Transfer Function

The jitter transfer function describes the amount of jitter in
specific equipment that is transferred from the input to the
output over a frequency range.

The jitter attenuator exhibits a single-pole rolloff (20 dB/
decade) jitter transfer characteristic that has no peaking
and a nominal filter corner frequency (3 dB bandwidth) for
DS1 and CEPT operation of less than 10 Hz. For a given
frequency, different jitter amplitudes will cause slight varia-
tions in attenuation because of finite quantization effects.
Jitter amplitudes of less than approximately 0.2 UI will have
greater attenuation than the single-pole rolloff characteris-
tic.

Measurement of the jitter transfer function involves stimu-
lating the circuit with a sinusoidal jitter test signal. The dif-
ference between the output signal power and the test
signal power, at a given frequency, is the jitter transfer.
When output signal power is below the noise floor, it cannot
be measured. Halting the jitter transfer function measure-
ments because of noise floor limitations is acceptable dur-
ing conformance testing.

8.4 Jitter Tolerance

The minimum jitter tolerance of the jitter attenuator occurs
when the XCLK frequency and the long-term average fre-
quency of the input clock are at their extreme-frequency tol-
erances. The minimum tolerance is 28 UI peak-to-peak at
the highest jitter frequency of 15 kHz.

8.5 Jitter Attenuator Enable

The jitter attenuator is selected using the JAR and JAT bits
(register 5, bits 1 and 2) of the microprocessor interface.
These control bits are global and affect all four channels
unless a given channel is in the powerdown mode
(PWRDN = 1). Because there is only one attenuator func-
tion in the device, selection must be made between either
the transmit or receive path. If both JAT and JAR are acti-
vated at the same time, the jitter attenuator will be disabled.
Note that the power consumption increases slightly on a
per-channel basis when the jitter attenuator is active, as
described in

Table 11-1

. If jitter attenuation is selected, a

valid XCLK (pin 29) signal must be available.

8.5.1 Jitter Attenuator Receive Path Enable (JAR)

When the jitter attenuator receive bit is set (JAR = 1), the
attenuator is enabled in the receive data path between the
clock/data recovery and the decoder (see

Figure 4-1

Under this condition, the jitter characteristics of the jitter
attenuator apply for the receiver. When JAR = 0, the clock/
data recovery outputs bypass the disabled attenuator and
directly enter the decoder function. The receive path will
then exhibit the jitter characteristics of the clock recovery
function as described in

Section 6.2

. If CDR = 0 (register 5,

bit 0), the JAR bit is ignored because clock recovery will be
disabled.

Table 8-1. List of Low-Bandwidth Jitter Specification

Documents

Application

DS1

CEPT

TR-TSY-000009, TR-TSY-000253,
TR-TSY-000499

ITU-T G.735

ITU-T I.431

T7690 5.0 V T1/E1 Quad Line Interface

Data Sheet

T7693 3.3 V T1/E1 Quad Line Interface

July 2002

8 Jitter Attenuator

(continued)

Agere Systems Inc.

8.5.2 Jitter Attenuator Transmit Path Enable (JAT)

When the jitter attenuator transmit bit is set (JAT = 1), the
attenuator is enabled in the transmit data path between the
encoder and the pulse-width controller/pulse equalizer (see

Figure 4-1

). Under this condition, the jitter characteristics of

the jitter attenuator apply for the transmitter. When JAT = 0,
the encoder outputs bypass the disabled attenuator and
directly enter the pulse-width controller/pulse equalizer.
The transmit path will then pass all jitter from TCLK to line
interface outputs TTIP/TRING.

8.6 Loopbacks

The device has three independent loopback paths that are
activated using LOOPA and LOOPB (registers 6 to 9, bits 3
and 4) as shown in Table 8-2. The locations of these loop-
backs are illustrated in

Figure 4-1

* During the transmit blue signal condition, the looped data will be the

transmitted data from the system and not the all-1s signal.

Transmit blue signal request is ignored.

8.6.1 Full Local Loopback (FLLOOP)

A full local loopback (FLLOOP) connects the transmit line
driver input to the receiver analog front-end circuitry. Valid
transmit output data continues to be sent to the network. If
the transmit blue signal (all-1s AIS signal) is sent to the net-
work, the looped data is not affected. The ALOS alarm con-
tinues to monitor the receive line interface signal while
DLOS monitors the looped data.

8.6.2 Remote Loopback (RLOOP)

A remote loopback (RLOOP) connects the recovered clock
and retimed data to the transmitter at the system interface
and sends the data back to the line. The receiver front end,
clock/data recovery, encoder/decoder (if enabled) jitter
attenuator (if enabled), and transmit driver circuitry are all
exercised during this loopback.

The transmit clock, transmit data, and TBS inputs are
ignored. Valid receive output data continues to be sent to
the system interface. This loopback mode is very useful for
isolating failures between systems.

8.6.3 Digital Local Loopback (DLLOOP)

A digital local loopback (DLLOOP) connects the transmit
clock and data through the encoder/decoder pair to the
receive clock and data output pins at the system interface.
This loopback is operational if the encoder/decoder pair is
enabled or disabled. The blue signal can be transmitted
without any effect on the looped signal.

8.7 Other Features

8.7.1 Powerdown (PWRDN)

Each line interface channel has an independent power-
down mode controlled by PWRDN (registers 6 to 9, bit 0).
This provides power savings for systems that use backup
channels. If PWRDN = 1, the corresponding channel will be
in a standby mode, consuming only a small amount of
power. It is recommended that the alarm registers for the
corresponding channel be masked with MASK = 1 (regis-
ters 6 to 9, bit 1) during powerdown mode. If a line interface
channel in powerdown mode needs to be placed into ser-
vice, the channel should be turned on (PWRDN = 0)
approximately 5 ms before data is applied.

If a line interface channel will never be in service, the V

DDA

and V

DDD

pins can be connected to the ground plane,

resulting in no power consumption.

8.7.2 RESET (RESET, SWRESET)

The device provides both a hardware reset (RESET;
pin 32) and a software reset (SWRESET; register 4, bit 1)
that are functionally equivalent. When the device is in reset,
all signal-path and alarm monitor states are initialized to a
known starting configuration. The status registers and INT
(pin 25) are also cleared. The writable microprocessor
interface registers are not affected by reset, with the excep-
tion of bits in register 4 (see

Section 9.6.3

). During a reset

condition, data transmission will be momentarily interrupted
and the device will respond to those register bits affected
by the reset. On powerup of the device, the software reset
bit (register 4, bit 1) is not initialized. It must be written to a
0 prior to writing the other bits in register 4.

Table 8-2. Loopback Control

Operation

Symbol

LOOPA

LOOPB

Normal

Full Local Loopback

FLLOOP*

Remote Loopback

RLOOP

Digital Local
Loopback

DLLOOP

Data Sheet

T7690 5.0 V T1/E1 Quad Line Interface

July 2002

T7693 3.3 V T1/E1 Quad Line Interface

8 Jitter Attenuator

(continued)

Agere Systems Inc.

The reset condition is initiated by setting RESET = 0 or
SWRESET = 1 for a minimum of 10 µs. After leaving the
reset condition (with RESET = 1 or SWRESET = 0), only
the bits in register 4 need to be restored.

8.8 Loss of XCLK Reference Clock (LOXC)

The LOXC output (pin 31) is active when the XCLK refer-
ence clock (pin 29) is absent. The LOXC flag is asserted
between 150 ns and 700 ns after XCLK disappears, and
deasserts immediately after detecting the first clock edge of
XCLK.

During the LOXC alarm condition, the clock recovery and
jitter attenuator functions are automatically disabled.
Therefore, if CDR = 1 and/or JAR = 1, the RCLK, RPD,
RND, and DLOS outputs will be unknown. If CDR = 0, there
will be no effect on the receiver. If the jitter attenuator is
enabled in the transmit path (JAT = 1) during this alarm
condition, then LOTC = 1 will also be indicated.

8.9 In-Circuit Testing and Driver 3-State (ICT)

The function of the ICT input (pin 33) is determined by the
ICTMODE bit (register 4, bit 3). If ICTMODE = 0 and ICT is
activated (ICT = 0), then all output buffers (TTIP, TRING,
RCLK, RPD, RND, LOXC, RDY_DTACK, INT, AD[7:0]) are
placed in a high-impedance state. For in-circuit testing, the
RESET pin can be used to activate ICTMODE = 0 without
having to write the bit. If ICTMODE = 1 and ICT = 0, then
only the TTIP and TRING outputs of all channels will be
placed in a high-impedance state. The TTIP and TRING
outputs have a limiting high-impedance capability of
approximately 8 k

Agere Systems Inc.

Data Sheet

July 2002

T7693 3.3 V T1/E1 Quad Line Interface

T7690 5.0 V T1/E1 Quad Line Interface

9 Microprocessor Interface

9.1 Overview

The device is equipped with a microprocessor interface
that can operate with most commercially available micro-
processors. Inputs MPMUX and MPMODE (pins 20 and
21) are used to configure this interface into one of four pos-
sible modes, as shown in Table 9-1. The MPMUX setting
selects either a multiplexed 8-bit address/data bus
(AD[7:0]) or a demultiplexed 4-bit address bus (A[3:0]) and
an 8-bit data bus (AD[7:0]). The MPMODE setting selects
the associated set of control signals required to access a
set of registers within the device.

When the microprocessor interface is configured to operate
in the multiplexed address/data bus modes (MPMUX = 1),
the user has access to an internal chip select function that
allows the microprocessor to selectively read/write a spe-
cific T7693 in a multiple T7693 environment (see

Section

9.5

The microprocessor interface can operate at speeds up to
16.384 MHz in interrupt-driven or polled mode without
requiring any wait-states.

For microprocessors operating at greater than 16.384 MHz,
the RDY_DTACK output is used to introduce wait-states in
the read/write cycles.

In the interrupt-driven mode, one or more device alarms will
assert the active-high INT output (pin 25) once per alarm
activation. After the microprocessor reads the alarm status
registers, the INT output will deassert. In the polled mode,
however, the microprocessor monitors the various device
alarm status by periodically reading the alarm status regis-
ters without the use of INT (pin 25). In both interrupt and
polled methods of alarm servicing, the status register will
clear on a microprocessor read cycle only when the alarm
condition within the signaling channel no longer exists; oth-
erwise, the register bit remains set.

Due to the device flexibility, there are no default power-up
or reset states, except for register 4. All read/write registers
must be written by the microprocessor on system start-up
to guarantee proper device functionality.

Details concerning microprocessor interface configuration
modes, pinout definitions, clock specifications, register
bank architecture, and the I/O timing specifications and dia-
grams are described in the following sections.

9.2 Microprocessor Configuration Modes

Table 9-1 highlights the four microprocessor modes controlled by the MPMUX and MPMODE inputs (pins 20 and 21).

Table 9-1. Microprocessor Configuration Modes

Mode

MPMODE

MPMUX

Address/Data Bus

Generic Control, Data, and Output Pin Names

MODE 1

DEMUXed

CS, AS, DS, R/W, A[3:0], AD[7:0], INT, DTACK

MODE 2

MUXed

CS, AS, DS, R/W, AD[7:0], INT, DTACK

MODE 3

DEMUXed

CS, ALE, RD, WR, A[3:0], AD[7:0], INT, RDY

MODE 4

MUXed

CS, ALE, RD, WR, AD[7:0], INT, RDY

Data Sheet

T7690 5.0 V T1/E1 Quad Line Interface

July 2002

T7693 3.3 V T1/E1 Quad Line Interface

9 Microprocessor Interface

(continued)

Agere Systems Inc.

9.3 Microprocessor Interface Pinout Definitions

The MODE [1--4] specific pin definitions are given in Table 9-2. Note that the microprocessor interface uses the same set
of pins in all modes.

Table 9-2. MODE [1--4] Microprocessor Pin Definitions

Configuration

Pin

Number

Device Pin

Name

Generic

Pin Name

Pin_Type

Assertion

Sense

Function

MODE 1

WR_DS

Input

Active-Low

Data Strobe

RD_R/W

R/W

Input

Read/Write

R/W = 1 => Read

R/W = 0 => Write

ALE_AS

Input

Address Strobe

Input

Active-Low

Chip Select

INT

Output

Active-High

Interrupt

RDY_DTACK

DTACK

Output

Active-Low

Data Acknowledge

69--76

AD[7:0]

I/O

Data Bus

79--82

A[3:0]

Input

Address Bus

MPCLK

Input

Microprocessor Clock

MODE 2

WR_DS

Input

Active-Low

Data Strobe

RD_R/W

R/W

Input

Read/Write

R/W = 1 => Read

R/W = 0 => Write

ALE_AS

Input

Address Strobe

Input

Active-Low

Chip Select

INT

Output

Active-High

Interrupt

RDY_DTACK

DTACK

Output

Active-Low

Data Acknowledge

69--76

AD[7:0]

I/O

Address/Data Bus

MPCLK

Input

Microprocessor Clock

MODE 3

WR_DS

Input

Active-Low

Write

RD_R/W

Input

Active-Low

Read

ALE_AS

ALE

Input

Address Latch Enable

Input

Active-Low

Chip Select

INT

Output

Active-High

Interrupt

RDY_DTACK

RDY

Output

Active-High

Ready

69--76

AD[7:0]

I/O

Data Bus

79--82

A[3:0]

Input

Address Bus

MPCLK

Input

Microprocessor Clock

MODE 4

WR_DS

Input

Active-Low

Write

RD_R/W

Input

Active-Low

Read

ALE_AS

ALE

Input

Address Latch Enable

Input

Active-Low

Chip Select

INT

Output

Active-High

Interrupt

RDY_DTACK

RDY

Output

Active-High

Ready

69--76

AD[7:0]

I/O

Address/Data Bus

MPCLK

Input

Microprocessor Clock

T7690 5.0 V T1/E1 Quad Line Interface

Data Sheet

T7693 3.3 V T1/E1 Quad Line Interface

July 2002

9 Microprocessor Interface

(continued)

Agere Systems Inc.

9.4 Microprocessor Clock (MPCLK) Specifications

The microprocessor interface is designed to operate at clock speeds up to 16.384 MHz without requiring any wait-states.
Wait-states may be needed if higher microprocessor clock speeds are required. The microprocessor clock (MPCLK, pin 83)
specification is shown in Table 9-3. This clock must be supplied only if the RDY_DTACK and INT outputs are required to be
synchronous to MPCLK. Otherwise, the MPCLK pin must be connected to ground (GND

9.5 Internal Chip Select Function

When the microprocessor interface is configured to operate in the multiplexed address/data bus modes (MPUX = 1), the
user has access to an internal chip select function. This function allows a microprocessor to selectively read or write a spe-
cific quad line interface device in a system of up to eight devices on the microprocessor bus. Externally tying CS = 0 (pin
24) and A3 = 1 (pin 79) on every line interface device enables the internal chip select function. Individual device addresses
are established by externally connecting the other three address pins A[2:0] to a unique address value in the range of 000
through 111. In order for a line interface device to respond to the register read or write request from the microprocessor, the
address data bus AD[6:4] (pins 70, 71, 72) must match the specific address defined on A[2:0]. If CS and A3 pins are tied
low, the internal chip select function is disabled and all line interface devices will respond to a microprocessor write request.
However, if CS = 1, none of the line interface devices will respond to the microprocessor read/write request.

9.6 Microprocessor Interface Register Architecture

The register bank architecture of the microprocessor interface is shown in

Table 9-4

. The register bank consists of sixteen

8-bit registers classified as alarm registers, global control registers, and channel configuration/maintenance registers. Reg-
isters 0 and 1 are the alarm registers used for storing the various device alarm status and are read-only. All other registers
are read/write. Registers 2 and 3 contain the individual mask bits for the alarms in registers 0 and 1. Registers 4 and 5 are
designated as the global control registers used to set up the functions for all four channels. The channel configuration reg-
isters in registers 6 through 9 are used to configure the individual channel functions and parameters. Registers 10 and 11
must be cleared by the user after a powerup for proper device operation. Registers 12 through 15 are reserved for propri-
etary functions and must not be addressed during operation. The following sections describe these registers in detail.

Table 9-3. Microprocessor Input Clock Specifications

Name

Symbol

Period and

Tolerance

rise

Typ

fall

Typ

Duty Cycle

Unit

Min High

Min Low

MPCLK

61 to 323

Data Sheet

T7690 5.0 V T1/E1 Quad Line Interface

July 2002

T7693 3.3 V T1/E1 Quad Line Interface

9 Microprocessor Interface

(continued)

Agere Systems Inc.

Notes:

A numerical suffix appended to the bit name identifies the channel number.

Bits shown in parentheses indicate the state forced during a reset condition.

All registers must be configured by the user before the device can operate as required for the particular application.

Registers 12--15 are reserved and should not be written. If they are written they must always be written with 0s.

Table 9-4. Register Set

Register

Address

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

Alarm Registers (Read Only)

0000

LOTC2

TDM2

DLOS2

ALOS2

LOTC1

TDM1

DLOS1

ALOS1

0001

LOTC4

TDM4

DLOS4

ALOS4

LOTC3

TDM3

DLOS3

ALOS3

Alarm Mask Registers (Read/Write)

0010

MLOTC2

MTDM2

MDLOS2

MALOS2

MLOTC1

MTDM1

MDLOS1

MALOS1

0011

MLOTC4

MTDM4

MDLOS4

MALOS4

MLOTC3

MTDM3

MDLOS3

MALOS3

Global Control Registers (Read/Write)

0100

HIGHZ4 (1)

HIGHZ3 (1)

HIGHZ2 (1)

HIGHZ1 (1)

ICTMODE (0)

LOSSTD

SWRESET

GMASK (1)

0101

LOSSD

ACM

ALM

DUAL

CODE

JAT

JAR

CDR

Channel Configuration Registers (Read/Write)

0110

EQA1

EQB1

EQC1

LOOPA1

LOOPB1

TBS1

MASK1

PWRDN1

0111

EQA2

EQB2

EQC2

LOOPA2

LOOPB2

TBS2

MASK2

PWRDN2

1000

EQA3

EQB3

EQC3

LOOPA3

LOOPB3

TBS3

MASK3

PWRDN3

1001

EQA4

EQB4

EQC4

LOOPA4

LOOPB4

TBS4

MASK4

PWRDN4

1010

1011

12--15

1100--

1111

RESERVED

T7690 5.0 V T1/E1 Quad Line Interface

Data Sheet

T7693 3.3 V T1/E1 Quad Line Interface

July 2002

9 Microprocessor Interface

(continued)

Agere Systems Inc.

9.6.1 Alarm Register Overview (0000, 0001)

The bits in the alarm registers represent the status of the transmitter and receiver alarms LOTC, TDM, DLOS, and ALOS
for all four channels as shown in Table 9-6. The alarm indicators are active-high and automatically clear on a microproces-
sor read if the corresponding alarm condition no longer exists. Persistent alarm conditions will cause the bit to remain set.
These are read-only registers.

* The numerical suffix identifies the channel number.

9.6.2 Alarm Mask Register Overview (0010, 0011)

The bits in the alarm mask registers in Table 9-6 allow the microprocessor to selectively mask each channel alarm and pre-
vent it from generating an interrupt. The mask bits correspond to the alarm status bits in the alarm registers and are active-
high to disable the corresponding alarm from generating an interrupt. These registers are read/write registers.

* The numerical suffix identifies the channel number.

Table 9-5. Alarm Registers

Bits

Symbol*

Description

Alarm Register (0)

0, 4

ALOS[1:2]

Analog loss-of-signal alarm for channels 1 and 2.

1, 5

DLOS[1:2]

Digital loss-of-signal alarm for channels 1 and 2.

2, 6

TDM[1:2]

Transmit driver monitor alarm for channels 1 and 2.

3, 7

LOTC[1:2]

Loss-of-transmit clock alarm for channels 1 and 2.

Alarm Register (1)

0, 4

ALOS[3:4]

Analog loss-of-signal alarm for channels 3 and 4.

1, 5

DLOS[3:4]

Digital loss-of-signal alarm for channels 3 and 4.

2, 6

TDM[3:4]

Transmit driver monitor alarm for channels 3 and 4.

3, 7

LOTC[3:4]

Loss-of-transmit clock alarm for channels 3 and 4.

Table 9-6. Alarm Mask Registers

Bits

Symbol*

Description

Alarm Mask Register (2)

0, 4

MALOS[1:2]

Mask analog loss-of-signal alarm for channels 1 and 2.

1, 5

MDLOS[1:2]

Mask digital loss-of-signal alarm for channels 1 and 2.

2, 6

MTDM[1:2]

Mask transmit driver monitor alarm for channels 1 and 2.

3, 7

MLOTC[1:2]

Mask loss-of-transmit clock alarm for channels 1 and 2.

Alarm Mask Register (3)

0, 4

MALOS[3:4]

Mask analog loss-of-signal alarm for channels 3 and 4.

1, 5

MDLOS[3:4]

Mask digital loss-of-signal alarm for channels 3 and 4.

2, 6

MTDM[3:4]

Mask transmit driver monitor alarm for channels 3 and 4.

3, 7

MLOTC[3:4]

Mask loss-of-transmit clock alarm for channels 3 and 4.

Data Sheet

T7690 5.0 V T1/E1 Quad Line Interface

July 2002

T7693 3.3 V T1/E1 Quad Line Interface

9 Microprocessor Interface

(continued)

Agere Systems Inc.

9.6.3 Global Control Register Overview (0100, 0101)

The bits in the global control registers in Table 9-7 and Table 9-8 allow the microprocessor to configure the various device
functions over all the four channels. All the control bits (with the exception of LOSSTD and ICTMODE) are active-high.
These are read/write registers.

9.6.4 Channel Configuration Register Overview (0110--1001)

The control bits in the channel configuration registers in

Table 9-9

are used to select equalization, loopbacks, AIS genera-

tion, channel alarm masking, and the channel powerdown mode for each channel (1--4). The PWRDN[1--4], MASK[1--4],
and TBS[1--4] bits are active-high. These are read/write registers.

Table 9-7. Global Control Register (0100)

Bit

Symbol

Description

Global Control Register (4)

GMASK

The GMASK bit globally masks all the channel alarms when GMASK = 1, preventing all the
receiver and transmitter alarms from generating an interrupt. GMASK = 1 after a device reset.

SWRESET

The SWRESET provides the same function as the hardware reset. It is used for device initial-
ization through the microprocessor interface. The software reset bit must be cleared after pow-
erup prior to writing any other bits in register 4.

LOSSTD

The LOSSTD bit selects the conformance protocol for the DLOS receiver alarm function.

ICTMODE

The ICTMODE bit changes the function of the

,&7

pin. ICTMODE = 0 after a device reset.

4--7

HIGHZ[1:4]

A HIGHZ bit is available for each individual channel. When HIGHZ = 1, the TTIP and TRING
transmit drivers for the specified channel are placed in a high-impedance state. HIGHZ[1:4] = 1
after a device reset.

Table 9-8. Global Control Register (0101)

Bit

Symbol

Description

Global Control Register (5)

CDR

The CDR bit is used to enable and disable the clock/data recovery function.

JAR

The JAR is used to enable and disable the jitter attenuator function in the receive path. The JAR
and JAT control bits are mutually exclusive; i.e., either JAR or the JAT control bit can be set, but not
both.

JAT

The JAT is used to enable and disable the jitter attenuator function in the transmit path. The JAT
and JAR control bits are mutually exclusive; i.e., either JAT or the JAR control bit should be set, but
not both.

CODE

The CODE bit is used to enable and disable the B8ZS/HDB3 zero substitution coding (decoding) in
the transmit (receive) path. It is used in conjunction with the DUAL bit and is valid only for single-rail
operation.

DUAL

The DUAL bit is used to select single or dual-rail mode of operation.

ALM

The ALM bit selects the transmit and receive data polarity (i.e., active-low or active-high). The ALM
and ACM bits are used together to determine the transmit and receive data retiming modes.

ACM

The ACM bit selects the positive or negative edge of the receive clock (RCLK[1:4]) for receive data
retiming. The ACM and ALM bits are used together to determine the transmit and receive data
retiming modes.

LOSSD

The LOSSD bit selects the shutdown function for the digital loss-of-signal alarm (DLOS).

Agere Systems Inc.

Data Sheet

T7690 5.0 V T1/E1 Quad Line Interface

July 2002

T7693 3.3 V T1/E1 Quad Line Interface

10 Timing Characteristics

10.1 I/O Timing

The I/O timing specifications for the microprocessor interface are given in Table 10-1. The microprocessor interface pins
use CMOS I/O levels. All outputs, except the address/data bus AD[7:0], are rated for a capacitive load of 50 pF. The
AD[7:0] outputs are rated for a 100 pF load. The minimum read and write cycle time is 200 ns for all device configurations.

Table 10-1. Microprocessor Interface I/O Timing Specifications

Symbol

Configuration

Parameter

Setup

(ns)

(Min)

Hold

(ns)

(Min)

Delay

(ns)

(Max)

Modes 1 and 2

Address Valid to AS Asserted (Read, Write)

AS Asserted to Address Invalid (Read, Write)

AS Asserted to DS Asserted

R/W High (Read) to DS Asserted

DS Asserted (Read, Write) to DTACK Asserted

DTACK Asserted to Data Valid (Read)

DS Asserted (Read) to Data Valid

DS Negated (Read, Write) to AS Negated

DS Negated (Read) to Data Invalid

t10

DS Negated (Read) to DTACK Negated

t11

AS (Read, Write) Asserted Width

150

t12

DS (Read) Asserted Width

100

t13

AS Asserted to R/W Low (Write)

t14

R/W Low (Write) to DS Asserted

t15

Data Valid to DS Negated (Write)

t16

DS Negated to DTACK Negated (Write)

t17

DS Negated to Data Invalid (Write)

t18

DS (Write) Asserted Width

100

t19

Modes 3 and 4

Address Valid to ALE Asserted Low (Read, Write)

t20

ALE Asserted Low (Read, Write) to Address Invalid

t21

ALE Asserted Low to RD Asserted (Read)

t22

RD Asserted (Read) to Data Valid

t23

RD Asserted (Read) to RDY Asserted

t24

RD Negated to Data Invalid (Read)

t25

RD Negated to RDY Negated (Read)

t26

ALE Asserted Low to WR Asserted (Write)

t27

CS Asserted to RDY Asserted Low

t28

Data Valid to WR Negated (Write)

t29

WR Asserted (Write) to RDY Asserted

t30

WR Negated to RDY Negated (Write)

t31

WR Negated to Data Invalid

t32

ALE Asserted (Read, Write) Width

150

t33

RD Asserted (Read) Width

100

t34

WR Asserted (Write) Width

100

T7690 5.0 V T1/E1 Quad Line Interface

Data Sheet

T7693 3.3 V T1/E1 Quad Line Interface

July 2002

10 Timing Characteristics

(continued)

Agere Systems Inc.

10.2 Interface Data Timing

* Refers to each individual bit period for JAT = 0 applications.
Refers to each individual bit period for JAT = 1 applications using a gapped TCLK.

5-1156(C)r.5

* Invert RCLK for ACM = 1.

Figure 10-9. Interface Data Timing (ACM = 0)

Table 10-2. Interface Data Timing

The digital system interface timing is shown in Figure 10-9 for ACM = 0. If ACM = 1, then the RCLK signal in Figure 10-9
will be inverted.

Symbol

Parameter

Min

Typ

Max

Unit

tTCLTCL

Average TCLK Clock Period:

DS1
CEPT

--
--

647.7
488.0

--
--

ns
ns

tTDC

TCLK Duty Cycle*
TCLK Minimum High/Low Time

100

--
--

tTDVTCL

Transmit Data Setup Time

tTCLTDX

Transmit Data Hold Time

tTCH1TCH2

Clock Rise Time (10%/90%)

tTCL2TCL1

Clock Fall Time (90%/10%)

tRCHRCL

RCLK Duty Cycle

tRDVRCH

Receive Data Setup Time

140

tRCHRDX

Receive Data Hold Time

180

tRCLRDV

Receive Propagation Delay

7 &/./,

73'

/, 8

71'/,

5&/./,

53'

/, 8

51'/,8

W7 &+7&+

W 7 &/7

W7'9

7 &/

W7 &/7';

W5&/5'9

W5'95&+

W 5&+5';

W7 &/7&/

Data Sheet

T7690 5.0 V T1/E1 Quad Line Interface

July 2002

T7693 3.3 V T1/E1 Quad Line Interface

10 Timing Characteristics

(continued)

Agere Systems Inc.

10.2.1 Logic Interface Characteristics

An internal 50 k

pull-up is provided on the ICT and RESET pins. An internal 100 k

pull-up is provided on the CS, XCLK,

and BCLK pins. This requires these input pins to sink no more than 20 µA. All buffers use CMOS levels.

* 100 pF allowed for AD[7:0] (pins 69 to 76).

10.3 XCLK Reference Clock

The device requires a high-frequency reference clock for both clock/data recovery and jitter attenuation options (CDR = 1,
JAR = 1, or JAT = 1). The XCLK signal (pin 29) is conditionally required if the MPCLK signal (pin 83) is not supplied for
interrupt generation in the microprocessor interface. For any other device configuration, XCLK is not required. If it is
required, XCLK must be a continuously active (i.e., ungapped, unjittered, and unswitched) and an independent reference
clock such as an external system oscillator or system clock for proper operation. It must not be derived from any recovered
line clock (i.e., from RCLK or any synthesized frequency of RCLK). The specifications for XCLK are defined in Table 10-4.

Table 10-3. Logic Interface Characteristics

Parameter

Symbol

Test Conditions

Min

Max

Unit

Input Voltage:

Low
High

GND

1.0

V
V

Input Leakage

1.0

µA

Output Voltage:

Low
High

5.0 mA

GND

1.0

0.5

DDD

V
V

Input Capacitance

3.0

Load Capacitance*

Table 10-4. XCLK Timing Specifications

Parameter

Value

Unit

Min

Typ

Max

Frequency

DS1
CEPT

--
--

24.704
32.768

--
--

MHz
MHz

Range

100

ppm

Duty Cycle

T7690 5.0 V T1/E1 Quad Line Interface

Data Sheet

T7693 3.3 V T1/E1 Quad Line Interface

July 2002

Agere Systems Inc.

11 Electrical Characteristics

11.1 Power Supply Bypassing

External bypassing is required for all channels. A 1.0 µF capacitor must be connected between V

X and GNDX. In addi-

tion, a 0.1 µF capacitor must be connected between V

DDD

and GND

, and a 0.1 µF capacitor must be connected between

DDA

and GND

. Ground plane connections are required for GNDX, GND

, and GND

. Power plane connections are also

required for V

X and V

DDD

. The need to reduce high-frequency coupling into the analog supply (V

DDA

) may require an

inductive bead to be inserted between the power plane and the V

DDA

pin of every channel.

External bypassing is also required for the microprocessor power supply pins. A 0.1 µF capacitor must be connected
between every pair of V

DDC

and GND

pins. V

DDC

and GND

are connected directly to the power and ground planes,

respectively.

Capacitors used for power supply bypassing should be placed as close as possible to the device pins for maximum effec-
tiveness.

11.2 Power Specifications

Device power specification includes power to the line for a specified data ones density. Power and temperature for the
T7690 device is as follows: V

= 5 V; T

= 25 °C. Power and temperature for the T7693 device is as follows: V

= 3.3 V;

= 25 °C.

* A single channel (receive and transmit paths) for 50% ones density data.
For standby purposes. If a channel will never be used, connecting all V

pins to the ground plane is recommended, resulting in no power consumption.

For nominal V

, T

= 25 °C. Every function and channel operational with 50% ones density.

§ For V

= 5.25 V and T

= 25 °C. Every function and channel operational with 100% ones density.

** For V

= 3.465 V and T

= 25 °C. Every function and channel operational with 100% ones density.

Table 11-1. Power Specifications

Parameter

T7690

T7693

Unit

DS1

CEPT

DS1

CEPT

Per Channel:*
CDR = 0, JAx = 0 (transmit, receiver in data slicing mode,
no jitter attenuator)
CDR = 1, JAx = 0 (transmit, receiver in clock recovery
mode, no jitter attenuator)
CDR = 1, JAx = 1 (transmit, receiver in clock recovery
mode, jitter attenuator active)
During Powerdown Mode (PWRDN = 1)

100

2.5

106

109

2.5

104

118

120

Quad Total:

Typical

Max

412

780

450

760

490

970**

405

720**

mW
mW

Data Sheet

T7690 5.0 V T1/E1 Quad Line Interface

July 2002

T7693 3.3 V T1/E1 Quad Line Interface

11 Electrical Characteristics

(continued)

Agere Systems Inc.

11.3 Absolute Maximum Ratings

Stresses in excess of the absolute maximum ratings can cause permanent or latent damage to the device. These are abso-
lute stress ratings only. Functional operation of the device is not implied at these or any other conditions in excess of those
given in the operational sections of this device specification. Exposure to absolute maximum ratings for extended periods
can adversely affect device reliability.

Table 11-2. Absolute Maximum Ratings

11.4 Handling Precautions

Although ESD protection circuitry has been designed into this device, proper precautions must be taken to avoid exposure
to electrostatic discharge (ESD) and electrical overstress (EOS) during all handling, assembly, and test operations. Agere
employs both a human-body model (HBM) and a charged-device model (CDM) qualification requirement in order to deter-
mine ESD-susceptibility limits and protection design evaluation. ESD voltage thresholds are dependent on the circuit
parameters used in each of the models, as defined by JEDEC's JESD22-A114 (HBM) and JESD22-C101 (CDM)
standards.

11.5 Operating Conditions

* Requirements under all loading conditions are the following: each single transmit pulse requires a 90 mA current spike from the power supply for

approximately 100 ns. Circuit pack routing of V

should minimize impedance.

Parameter

Min

Max

Unit

dc Supply Voltage

0.5

6.5

Storage Temperature

125

°C

Maximum Voltage (digital pins) with Respect to V

DDD

0.5

Minimum Voltage (digital pins) with Respect to GND

0.5

Maximum Allowable Voltages (RTIP[1--4], RRING[1--4]) with Respect to V

0.5

Minimum Allowable Voltages (RTIP[1--4], RRING[1--4]) with Respect to GND

0.5

Table 11-3. Handling Precaution

Device

Minimum HBM Threshold

Minimum CDM Threshold

T7690

>1500 V

>2000 V

T7693

>1000 V

>2000

Table 11-4. Recommended Operating Conditions

Parameter

Symbol

Min

Typ

Max

Unit

Ambient Temperature

°C

T7690 Power Supply

4.75

5.0

5.25

T7693 Power Supply*

3.135

3.3

3.465

T7690 5.0 V T1/E1 Quad Line Interface

Data Sheet

T7693 3.3 V T1/E1 Quad Line Interface

July 2002

Agere Systems Inc.

12 External Line Termination Circuitry

12.1 T7690

The transmit and receive tip/ring connections provide a matched interface to the cable (i.e., terminating impedance
matches the characteristic impedance of the cable). The diagram in Figure 12-1 shows the appropriate external compo-
nents to interface to the cable for a single transmit/receive channel. The component values are summarized in Table 12-1,
based on the specific application.

5-3693(C).d

Figure 12-1. T7690 External Line Termination Circuitry

* Resistor tolerances are ±1%. Transformer turns ratio tolerances are ±2%.
For CEPT 75

applications, option 1 is recommended over option 2 for lower device power dissipation.

Table 11-1

shows the power for option 1; option

2 increases power dissipation by 13 mW per channel when driving 50% ones data. Option 2 allows for the same transformer as used in CEPT 120

applications.

A ±5% tolerance is allowed for the transmit load termination.

Table 12-1. Termination Components by Application*

Symbol

Name

Cable Type

Unit

DS1

Twisted Pair

CEPT 75

Coaxial

CEPT 120

Twisted Pair

Option 1

Option 2

Center Tap Capacitor

0.1

µF

Receive Primary Impedance

200

Receive Series Impedance

71.5

28.7

174

Receive Secondary Impedance

113

82.5

102

205

Equivalent Line Termination

100

120

Tolerance

±4

Transmit Series Impedance

26.1

15.4

26.1

Transmit Load Termination

100

120

Transformer Turns Ratio

1.14

1.08

1.36

57,3

55,1*

77,3

75,1*

'(9,&(

&+$11(/

5(&(,9( '$7$

75$160,7 '$7$

75$16)250(5

(48,30(17

,17(5)$&(

Data Sheet

T7690 5.0 V T1/E1 Quad Line Interface

July 2002

T7693 3.3 V T1/E1 Quad Line Interface

12 External Line Termination Circuitry

(continued)

Agere Systems Inc.

12.2 T7693

The transmit and receive tip/ring connections provide a matched interface to the cable (i.e., terminating impedance
matches the characteristic impedance of the cable). The diagram in Figure 12-2 shows the appropriate external compo-
nents to interface to the cable for a single transmit/receive channel. The component values are summarized in Table 12-2,
based on the specific application.

5-3693(C).dr.1

Figure 12-2. T7693 External Line Termination Circuitry

* Resistor tolerances are ±1%. Transformer turns ratio tolerances are ±2%.
For CEPT 75

applications, option 1 is recommended over option 2 for lower device power dissipation.

Table 11-1

shows the power for option 1; option

2 increases power dissipation by 13 mW per channel when driving 50% ones data. Option 2 allows for the same transformer as used in CEPT 120

applications.

A ±5% tolerance is allowed for the transmit load termination.

Table 12-2. Termination Components by Application*

Symbol

Name

Cable Type

Unit

DS1

Twisted Pair

CEPT 75

Coaxial

CEPT 120

Twisted Pair

Option 1

Option 2

Center Tap Capacitor

0.1

µF

Receive Primary Impedance

200

Receive Series Impedance

336

143

261

698

Receive Secondary Impedance

210

147

182

365

Equivalent Line Termination

100

120

Tolerance

±4

Transmit Series Impedance

7.5

5.36

7.5

Transmit Load Termination

100

120

Transformer Turns Ratio

2.1

1.91

2.42

57,3

55,1*

77,3

75,1*

'(9,&(

&+$11(/

5(&(,9( '$7$

75$160,7 '$7$

75$16)250(5

(48,30(17

,17(5)$&(

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Document Outline

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