TM
Document ID#: 080211 Date:
Dec 6, 2005
Rev:
I
Version: 1
Distribution:
Public Document
Le79R70
Ringing Subscriber Line Interface Circuit
VE580 Series
APPLICATIONS
Integrated Access Devices (IADs)
Network Interface Units (NIUs)
Cable Modems
DSL Modems
Set Top / House Side Boxes
Intelligent PBX
Pain Gain
FXS Cards
Voice over ISDN or T1/E1
Smart Residential Gateways
WLL, APON, FITL, NGN, and all other short-loop CPE/
Enterprise telephony applications
FEATURES
Ideal for ISDN-TA and set top applications
On-chip ringing with on-chip ring-trip detector
Low Standby state power
Battery operation:
-- VBAT1: 40 V to 67 V
-- VBAT2: 19 V to VBAT1
On-chip battery switching and feed selection
On-hook transmission
Polarity reversal option
Programmable constant-current feed
Programmable open circuit voltage
Programmable loop-detect threshold
Current gain = 1000
Two-wire impedance set by single component
Ground-key detector
Tip Open state for ground-start lines
Internal VEE regulator (no external 5 V power supply
required)
Two on-chip relay drivers and snubber circuits
Space-saving package options (8x8 QFN)
RELATED LITERATURE
080917 VE790 Series RSLIC Device Product Brief
080158 Le79R70/79/100/101 Ringing SLIC Devices
Technical Overview
080255 Le71HE0040J Evaluation Board User's Guide
080753 Le58QL02/021/031 QLSLACTM Data Sheet
ORDERING INFORMATION
1.
Legerity reserves the right to fulfill all orders for this device with
parts marked with the "Am" part number prefix, until such time as
all inventory bearing this mark has been depleted. It should be
noted that parts marked with either the "Am" or the "Le" part
number prefix are equivalent devices in terms of form, fit, and
function. The only difference between the two is in the part
number prefix appearing on the topside mark.
2.
Green package meets RoHS Directive 2002/95/EC of the
European Council to minimize the environmental impact of
electrical equipment.
3.
Due to size constraints, QFN devices are marked by omitting the
"Le" prefix and the performance grade dash character. For
example, Le79R70-1QC is marked 79R701QC.
4.
Not available for new customers.
5.
For delivery using a tape and reel packing system, add a "T" suffix
to the OPN (Ordering Part Number) when placing an order.
Device
1
Package Type
2, 3
Packing
5
Le79R70JC
32-pin PLCC, No Pol. Rev.
Tube
Le79R70DJC
32-pin PLCC, No Pol. Rev.
(Green package)
Tube
Le79R70-1JC
32-pin PLCC, Pol. Rev.
Tube
Le79R70-1DJC
32-pin PLCC, Pol. Rev.
(Green package)
Tube
Le79R70QC
32-pin QFN, No Pol. Rev.
Tray
Le79R70-1QC
32-pin QFN, Pol. Rev.
Tray
Le79R70-1FQC
32-pin QFN, Pol. Rev.
(Green package)
Tray
DESCRIPTION
The Le79R70 Ringing Subscriber Line Interface Circuit
(RSLIC) device is a bipolar monolithic SLIC that offers on-chip
ringing. Designers can achieve significant cost reductions at
the system level for short-loop applications by integrating the
ringing function on chip. Examples of such applications would
be ISDN Terminal Adaptors and set top boxes. Using a CMOS-
compatible input waveform and wave shaping R-C network,
the Le79R70 Ringing SLIC device can provide trapezoidal
wave ringing to meet various design requirements.
See the
Le79R70 Block Diagram, on page 3
.
2
Le79R70 VE580 Series Data Sheet
TABLE OF CONTENTS
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Related literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Product Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Connection Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Operating Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Environmental Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Relay Driver Schematic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
DC Feed Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Ring-Trip Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Test Circuits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Application Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Physical Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
32-Pin PLCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
32-Pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Revision A to B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Revision B to C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Revision C to D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Revision D to E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Revision E to F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Revision F to G1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Revision G1 to H1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Revision H1 to I1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Le79R70 VE580 Series Data Sheet
3
PRODUCT DESCRIPTION
The Legerity family of subscriber line interface circuit (SLIC) products provide the telephone interface functions required
throughout the worldwide market. Legerity SLIC devices address all major telephony markets including central office (CO),
private branch exchange (PBX), digital loop carrier (DLC), fiber-in-the-loop (FITL), radio-in-the-loop (RITL), hybrid fiber coax
(HFC), and video telephony applications.
The Legerity SLIC devices offer support of BORSHT (battery feed, over voltage protection, ringing, supervision, hybrid, and test)
functions with features including current limiting, on-hook transmission, polarity reversal, tip-open, and loop-current detection.
These features allow reduction of line card cost by minimizing component count, conserving board space, and supporting
automated manufacturing.
The Legerity SLIC devices provide the two- to four-wire hybrid function, DC loop feed, and two-wire supervision. Two-wire
termination is programmed by a scaled impedance network. Transhybrid balance can be achieved with an external balance
circuit or simply programmed using a companion Legerity codec device, the Le79C02/03/031 DSLACTM device, the Le79Q02/
021/031 Programmable Quad SLAC (QSLACTM) device, or the Le79Q5457/4457 Non-programmable QSLAC device.
The Le79R70 Ringing SLIC device is a bipolar monolithic SLIC that offers on-chip ringing. Now designers can achieve significant
cost reductions at the system level for short-loop applications by integrating the ringing function on chip. Examples of such
applications would be ISDN Terminal Adaptors and set top boxes. Using a CMOS-compatible input waveform and wave shaping
R-C network, the Le79R70 Ringing SLIC can provide trapezoidal wave ringing to meet various design requirements.
In order to further enhance the suitability of this device in short-loop, distributed switching applications, Legerity has maximized
power savings by incorporating battery switching on chip. The Le79R70 Ringing SLIC device switches between two battery
supplies such that in the Off-hook (active) state, a low battery is used to save power. In order to meet the Open Circuit voltage
requirements of fax machines and maintenance termination units (MTU), the SLIC automatically switches to a higher voltage in
the On-hook (standby) state.
Like all of the Legerity SLIC devices, the Le79R70 Ringing SLIC device supports on-hook transmission, ring-trip detection and
programmable loop-detect threshold. The Le79R70 Ringing SLIC device is a programmable constant-current feed device with
two on-chip relay drivers to operate external relays. This unique device is available in the proven Legerity 75 V bipolar process.
Figure 1. Le79R70 Block Diagram
E1
D2
D1
Two-Wire
Interface
HPA
HPB
Input Decoder
and Control
Relay
Driver
Ring-Trip
Detector
Power-Feed
Controller
RTRIP1
RTRIP2
BGND
VCC VNEG
RD
RDC
AGND/DGND
VBAT2
A(TIP)
B(RING)
RYOUT1
RDCR
C1
Switch
Driver
VBAT1
RSGL
Ground-Key
Detector
Off-Hook
Detector
Relay
Driver
RYOUT2
C2
C3
RSGH
B2EN
RSN
VTX
Signal
Transmission
RINGIN
RYE
DET
4
Le79R70 VE580 Series Data Sheet
CONNECTION DIAGRAM
1
32-pin QFN
RSN
VNEG
VTX
RDCR
RINGIN
HPA
HPB
RTRIP2
21
20
19
18
17
22
23
24
E1
C3
C2
RYE
RYOUT1
B2EN
VBAT1
D1
2
3
4
5
6
7
8
C1
D2
AGND/
DGND
RSGL
RDC
N/C
RSGH
10
9
12
11
14
13
16
15
RTRIP1
A(TIP)
RD
B(RING)
VBAT2
BGND
VCC
RYOUT2
32
31
30
29
28
27
26
25
DET
Exposed Pad
Notes:
1.
Pin 1 is marked for orientation.
2.
NC = No connect
3.
RSVD = Reserved. Do not connect to this pin.
4.
The thermally enhanced QFN package features an exposed pad on the underside which must be electrically tied to VBAT1.
RSVD
E1
C3
C2
DET
C1
RSGH
RSGL
RDC
RSN
AGND/
DGND
VBAT1
B2EN
RSVD
VBAT2
VCC
BGND
RTRIP1
B(RING)
RD
A(TIP)
RTRIP2
1
2
3
4
5
6
7
8
9
10
11
28
27
26
25
24
23
22
21
20
19
18
17
16
15
12
13
14
HPB
HPA
RINGIN
VNEG
VTX
RDCR
28-Pin
SOIC
32-Pin PLCC
RTRIP1
4
3
2
1
32 31 30
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
D1
HPB
HPA
VNEG
RSN
26
27
28
29
RYOUT1
C2
RYE
VTX
B2EN
RDCR
RYOUT2
VBAT1
E1
C3
D2
NC
RDC
RTRIP2
RINGIN
VCC
VBAT2
BGND
B(RING)
A(TIP)
RD
C1
RSGH
RSGL
AGND/D
G
ND
DET
Le79R70 VE580 Series Data Sheet
5
Pin Descriptions
Pin Names
Type
Description
AGND/DGND
Gnd
Analog and digital ground are connected internally to a single pin.
A(TIP)
Output
Output of A(TIP) power amplifier.
B2EN
Input
V
BAT2
enable. Logic Low enables operation from V
BAT2
. Logic High enables operation from V
BAT1
. TTL
compatible.
BGND
Gnd
Battery (power) ground
B(RING)
Output
Output of B(RING) power amplifier.
C3C1
Input
Decoder. TTL compatible. C3 is MSB and C1 is LSB.
D1
Input
Relay1 control. TTL compatible. Logic Low activates the Relay1 relay driver.
D2
Input
(Option) Relay2 control. TTL compatible. Logic Low activates the Relay2 relay driver.
DET
Output
Detector. Logic Low indicates that the selected detector is tripped. Logic inputs C3C1 and E1 select the
detector. Open-collector with a built-in 15 k
pull-up resistor.
E1
Input
(Option) A logic High selects the off-hook detector. A logic Low selects the ground-key detector. TTL
compatible.
HPA
Capacitor
High-pass filter capacitor. A(TIP) side of high-pass filter capacitor.
HPB
Capacitor
High-pass filter capacitor. B(RING) side of high-pass filter capacitor.
RD
Resistor
Detect resistor. Threshold modification and filter point for the off-hook detector.
RDC
Resistor
DC feed resistor. Connection point for the DC-feed current programming network, which also connects to the
receiver summing node (RSN). V
RDC
is negative for normal polarity and positive for reverse polarity.
RDCR
--
Connection point for feedback during ringing.
RINGIN
Input
Ring Signal Input. Pin for ring signal input. Square-wave shaped by external RC filter. Requires 50% duty
cycle. CMOS-compatible input.
RSGH
Input
Saturation Guard High. Pin for resistor to adjust Open Circuit voltage when operating from V
BAT1
.
RSGL
Input
Saturation Guard Low. Pin for resistor to adjust the anti-saturation cut-in voltage when operating from both
V
BAT1 and
V
BAT2
.
RSN
Input
The metallic current (AC and DC) between A(TIP) and B(RING) is equal to 1000 x the current into this pin.
The networks that program receive gain, two-wire impedance, and feed resistance all connect to this node.
RTRIP1
Input
Ring-trip detector. Ring-trip detector threshold set and filter pin.
RTRIP2
Input
Ring-trip detector threshold offset (switch to V
BAT1
). For power conservation in any non-ringing state, this
switch is open.
RYE
Output
Common Emitter of RYOUT1/RYOUT2. Emitter output of RYOUT1 and RYOUT2. Normally connected to
relay ground.
RYOUT1
Output
Relay/switch driver. Open-collector driver with emitter internally connected to RYE.
RYOUT2
Output
(Option) Relay/switch driver. Open-collector driver with emitter internally connected to RYE.
VBAT1
Battery
Battery supply and connection to substrate.
VBAT2
Battery
Power supply to output amplifiers. Connect to off-hook battery through a diode.
VCC
Power
Positive analog power supply.
VNEG
Power
Negative analog power supply. This pin is the return for the internal VEE regulator.
VTX
Output
Transmit Audio. This output is a 0.5066 gain version of the A(TIP) and B(RING) metallic AC voltage. VTX also
sources the two-wire input impedance programming network.
Exposed Pad
Battery
This must be electrically tied to VBAT1.
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