XR-T5794

...the analog plus company

Quad E-1 Line

Interface Unit

Rev. 2.02

1994

EXAR Corporation, 48720 Kato Road, Fremont, CA 94538

(510) 668-7000

(510) 668-7017

June 1997-3

FEATURES

Meets CCITT G.703 Pulse Mask Template for
2.048Mbps (E1) Rates

Transmitter and Receiver Interfaces Can Be:

Single Ended, 75

Capacitive or Transformer

Coupled

Balanced, 100 or 120

Transformer Coupled

Minimum Return Loss is 20dB (Receive) and 18dB
(Transmit), Exceeds G.703 and ETSI 300 166
Specifications

Bipolar Outputs can be Disabled Individually (High Z
Outputs)

System Interface is TTL Compatible on Digital Input
and TTL/CMOS Compatible On Digital Output Pins

Individual Channel Loss of Signal Detection, Local
and Remote Digital Loopback

Fifth Driver For Monitoring and Testing

Low Power, CMOS Technology

Over-temperature Protection

APPLICATIONS

Multi-Line E1 Interface Cards

E1 Network Equipment

Multiplexers

Cross Connects

Switching Systems

Fault Tolerant Systems

GENERAL DESCRIPTION

The XR-T5794 is an optimized line interface unit, built
using low power CMOS technology. The device contains
four independent E1 channels for primary rate, PCM
applications up to 2.048Mbps. Each channel performs
the driver and receiver functions necessary to convert
bipolar signals to TTL/CMOS compatible logic levels and
vice versa. The device supports single ended or
balanced line interfaces on each channel, thereby
providing the user an option of reducing system cost and
board space by replacing the transformer with a
capacitor.

Each of the four drivers can be independently disabled,
allowing maximum flexibility in system power
management. Output pulses are fully CCITT G.703
compliant. Moreover, the return loss is at least 18dB over
a frequency range of 51kHz to 3.072MHz.

The slicing circuit in the receive path is able to tolerate a
maximum of 12dB of cable loss with a minimum input

sensitivity of 600mV over the operating temperature
range. Return loss on the receive interfaces is minimum
20dB from 51kHz to 3.072MHz.

Local and remote loopbacks can be performed on any of
the four channels. A separate loss of signal (LOS)
detection circuitry and a LOS pin is provided for each
input. A fifth transmitter has been provided to support
dedicated monitoring and testing purposes on any of the
eight bipolar paths. For designers not requiring the fifth
(monitor) driver, EXAR offers the XR-T5793, a pin
compatible version of the XR-T5794.

The XR-T5794 is targeted for multi-line E1 line card
applications where real estate, low power consumption
and back-up redundancy are critical. Also, the device
may be used in T1 applications (1.544Mbps) which do not
require meeting the DSX-1 cross connect pulse template.

ORDERING INFORMATION

Part No.

Package

Operating

Temperature Range

XR-T5794IJ

68 Lead PLCC

-40

C to +85

XR-T5794IV

80 Lead TQFP (14x14x1.4 mm)

-40

C to +85

XR-T5794

Rev. 2.01

BLOCK DIAGRAM

Slice

Voltage

Detector

Level

120

Impedance Selectable

(Without Transformer)

Tristate Drivers

Return Loss

Exceeds

Transceiver 2

Transceiver 1

0.47

TIP

Unbalanced

Receivers. Return Loss

Exceeds G.703

120

Balanced

(or 100

)

Detector

Transceiver 4

Transceiver 3

LOS

RXPOS

RXNEG

Slicer

Peak

RXIN

E1/T1-

100

RX INPUT

TIP

RING

LOS Threshold Based on G.775

LOOPEN(1.4)

LPMOD(1.4)

TXPOS

TXNEG

TXCLK

Driver

TXOUT

TXEN

OUT

TX OUTPUT

TIP

RING

Impedance

Selectable

120

,100

or 75

balanced

Unbalanced

ETSI 300 166

TIP

0.47

Channel 1

MOUT

Driver

MUX

Channel 2

Channel 3

Channel 4

Note

OUT

= 68

for 120

line impedance, R

OUT

= 62

for 100

line impedance, R

OUT

= 68

for 75

line impedance

MSEL (0.2)

MONEM

(Without Transformer)

Figure 1. Block Diagram

L
o
c
a

l
/

L
o
o
p
b
a
c
k

PE65834
TTI 7148

PE65839
TTI 7149

OUT

XR-T5794

Rev. 2.01

PIN CONFIGURATION

68 Lead PLCC

LOSLVS

TXCLK2

TXPOS2

TXNEG2

TXCLK1

TXPOS1

TXNEG1

LOOPEN2

LOOPEN1

E1/T1-

RXPOS2

RXNEG2

RXPOS1

RXNEG1

MONEN

TCLK4

TXPOS4

TXNEG4

TXCLK3

TXPOS3

TXNEG3

LOOPEN4

LOOPEN3

GND

RXPOS3

RXNEG3

RXPOS4

RXNEG4

LPMOD4

LPMOD3

RXIN4

LOS4

LOS3

RXIN3

MSEL0

MSEL1

RGND

MSEL2

RXIN2

LOS1

LOS2

RXIN1

LPMOD2

LPMOD1

TXEN3

TXEN4

TXOUT4

TXOUT3

AGND

MOUT

AGND

TXOUT1

TXOUT2

TXEN1

TXEN2

80 Lead TQFP (14 x 14 x 1.4 mm)

MONEN

TXCLK4

TXPOS4

TXNEG4

TXCLK3

TXPOS3

TXNEG3

LOOPEN4

LOOPEN3

GND

RXPOS3

RXNEG3

RXPOS4

RXNEG4

LPMOD4

LPMOD3

RXIN4

LOS4

LOS3

RXIN3

MSEL0

MSEL1

RGND

MSEL2

RXIN2

LOS1

LOS2

RXIN1

LPMOD2

LPMOD1

RXNEG1

RXPOS1

RXNEG2

RXPOS2

E1/T1-

LOOPEN1

LOOPEN2

TXNEG1

TXPOS1

TXCLK1

TXNEG2

TXPOS2

TXCLK2

LOSL

2 1 68

NC
NC

TXEN2
TXEN1

TXOUT1

TXOUT2

AGND

TXOUT3

TXOUT4

TXEN4
TXEN3

MOUT

XR-T5794

Rev. 2.01

PIN DESCRIPTION

PLCC

Pin #

SQFP

Pin #

Symbol

Type

Description

MOUT

Signal Monitor Output. If MONEN=1, this output tracks the selected signal.
Hi-Z otherwise. The channel selection is done using MONSEL[2..0] inputs.

Transmit V

DD.

)

5V (

5%).

AGND

GND

Analog Ground.

TXOUT3

Transmitter 3 Output. Transmitter 3 bipolar output connected to coupling
capacitor or pulse transformer by a resistor.

Transmit V

SS.

-5V (

5%).

Transmit V

DD.

+5V (

5%).

TXOUT4

Transmitter 4 Output. Transmitter 4 bipolar output connected to coupling
capacitor or pulse transformer by a resistor.

TXEN4

Transmitter 4 Output Enable. If driven high the transmitter 4 output drivers
are enabled. Hi-Z otherwise.

TXEN3

Transmitter 3 Output Enable. If driven high the transmitter 3 output drivers
are enabled. Hi-Z otherwise.

MONEN

Monitor/Test Output Enable. If driven high the output driver of the MOUT
output is enabled. Hi-Z otherwise.

3,4

Analog V

DD.

TXCLK4

Transmitter 4 Clock Input. Apply logic one when RZ signals are supplied to
data inputs.

TXPOS4

Transmitter 4 Positive Data In. Positive data input in NRZ or RZ format for
transmitter 4.

TXNEG4

Transmitter 4 Negative Data In. Negative data input in NRZ or RZ format for
transmitter 4.

TXCLK3

Transmitter 3 Clock Input. Apply logic one when RZ signals are supplied to
data inputs.

TXPOS3

Transmitter 3 Positive Data In. Positive data input in NRZ or RZ format for
transmitter 3.

TXNEG3

Transmitter 3 Negative Data In. Negative data input in NRZ or RZ format for
transmitter 3.

LOOPEN4

Loop Enable 4. If driven high the specified loop type will be enabled for chan-
nel 4. Otherwise normal operation will continue.

LOOPEN3

Loop Enable 3. If driven high the specified loop type will be enabled for chan-
nel 3. Otherwise normal operation will continue.

GND

Digital Ground.

Digital V

DD.

+5V (

5%).

RXPOS3

Receiver 3 Positive Data Out. Positive data output in NRZ or RZ format for
receiver 3.

RXNEG3

Receiver 3 Negative Data Out. Negative data output in NRZ or RZ format for
receiver 3.

RXPOS4

Receiver 4 Positive Data Out. Positive data output in NRZ or RZ format for
receiver 4.

XR-T5794

Rev. 2.01

PIN DESCRIPTION (CONT'D)

PLCC

Pin #

SQFP

Pin #

Symbol

Type

Description

RXNEG4

Receiver 4 Negative Data Out. Negative data output in NRZ or RZ format for
receiver 4.

19, 20

Receive V

DD.

+5V (

5%).

LPMOD4

Loop Mode 4. If driven high the loopback mode of channel 4 will be set to re-
mote loop. Otherwise theloopback mode will remain at local loop. The
actual loopback will be activated when the LOOPEN4 is asserted.

LPMOD3

Loop Mode 3. If driven high the loopback mode of channel 3 will be set to re-
mote loop. Otherwise the loopback mode will remain at local loop. The
actual loopback will be activated when the LOOPEN3 is asserted.

RXIN4

Receiver 4 Input. Receiver 4 bipolar input connected to coupling capacitor or
pulse transformer.

LOS4

Receiver 4 Loss Of Signal. Asserted during LOS condition. Clear otherwise.

LOS3

Receiver 3 Loss Of Signal. Asserted during LOS condition. Clear otherwise.

RXIN3

Receiver 3 Input. Receiver 3 bipolar input connected to coupling capacitor or
pulse transformer.

MSEL0

Monitor Channel Select 0. Select line, used to select a channel for monitoring
using the MOUT pin based on the following assignment:

MSEL2 MSEL1 MSEL0 SELECTS

0 0 0 Line 1 Receive
0 0 1 Line 2 Receive

0 1 0 Line 3 Receive
0 1 1 Line 4 Receive
1 0 0 Line 1 Transmit
1 0 1 Line 2 Transmit
1 1 0 Line 3 Transmit
1 1 1 Line 4 Transmit

Note
The monitoring is only done on the NRZ data output signals from

the receiver or from the

transmitter line side.

MSEL1

Monitor Channel Select 1. See table above.

29, 30

RGND

GND

Receive Ground.

RGND

GND

Receive Ground.

MSEL2

Monitor Channel Select 2. See table above.

RXIN2

Receiver 2 Input. Receiver 2 bipolar input connected to coupling capacitor or
pulse transformer.

LOS1

Receiver 1 Loss Of Signal. Asserted during LOS condition. Clear otherwise.

LOS2

Receiver 2 Loss Of Signal. Asserted during LOS condition. Clear otherwise.

RXIN1

Receiver 1 Input. Receiver 1 bipolar input connected to coupling capacitor or
pulse transformer.

LPMOD2

Loop Mode 2. If driven high the loopback mode of channel 2 will be set to re-
mote loop. Otherwise the loopback mode will remain at local loop. The
actual loopback will be activated when the LOOPEN2 is asserted.

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