™
Le79R79
Ringing Subscriber Line Interface Circuit
VE580 Series
APPLICATIONS
Ideal for short-loop applications
Ideal for ISDN-TA and fixed radio access 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
ORDERING INFORMATION
The table below lists the valid device configurations available.
Construct your part number as follows:
Device + Pol. + Pkg. Option
For example: Le79R79-4JC
Device
1
Pol.
-1
Le79R79
-2
-3
-4
Package
Options
JC
DJC
QC
FQC
Package Type
2, 3
32-pin PLCC
32-pin PLCC
(Green package)
32-pin QFN
32-pin QFN
(Green package)
Packing
4
Tube
Tube
Tray
Tray
-1: 52 dB Longitudinal Balance, Polarity Reversal
-2: 63 dB Longitudinal Balance, Polarity Reversal
-3: 52 dB Longitudinal Balance, No Polarity Reversal
-4: 63 dB Longitudinal Balance, No Polarity Reversal
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.
Due to size constraints, QFN devices are marked by omitting the
“Le” prefix and the performance grade dash character. For
example, Le79R79-1QC is marked 79R791QC.
The green package. meets RoHS Directive 2002/95/EC of the
European Council to minimize the environmental impact of
electrical equipment.
For delivery using a tape and reel packing system, add a "T" suffix
to the OPN (Ordering Part Number) when placing an order.
FEATURES
Through trapezoidal ringing
On-chip ring-trip detector
Low standby state power
Battery operation:
— V
BAT1
: –40.5 to –75 V
— V
BAT2
: –19 V to V
BAT1
On-chip battery switching and feed selection
On-hook transmission
Two-wire impedance set by single external impedance
Programmable constant-current feed
Programmable Open Circuit voltage
Programmable loop-detect threshold
Current gain = 1000
Ground-key detector
Polarity reversal option available
Internal V
EE
regulator (no external –5 V power supply
required)
2.
3.
4.
DESCRIPTION
The Le79R79 Ringing SLIC 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, fiber-in-the-
loop, radio-in-the-loop, hybrid fiber/coax and video telephony
(home-side) boxes. The Le79R79 Ringing SLIC device can
provide sufficient voltage to meet the stringent LSSGR five-
ringer equivalent specification. Using a CMOS-compatible
input waveform and wave shaping R-C network, the Le79R79
Ringing SLIC device can provide trapezoidal wave ringing to
meet various design requirements.
See the
Le79R79 Block Diagram,
on page 3.
RELATED LITERATURE
080917 VE790 Series RSLIC Device Product Brief
080158 Le79R70/79/100/101 Technical Overview
080914 Le79R79 RSLIC Device User’s Guide
080810 Le71HR0021 Reference Design User’s Guide
080255 Le71HE0040J Evaluation Board User’s Guide
080458 Le79R100/101 v. Le79R79 Comparison Brief
080753 Le58QL02/021/031 QLSLAC™ Data Sheet
Document ID#:
080152
Date:
Dec 6, 2005
Rev:
M
Version:
1
Distribution:
Public Document
TABLE OF CONTENTS
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Related Literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Ordering Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Product Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Connection Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Operating Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Transmission Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Longitudinal Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Idle Channel Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Insertion Loss and Four-to-Four-Wire Balance Return Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Line Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Power Supply Rejection Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Supply Currents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Logic Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Logic Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Ring-Trip Detector Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Ring Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Ground-Key Detector Thresholds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Loop Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Relay Driver Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
relay driver schematic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
SLIC Device Decoding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
User-Programmable Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
DC Feed Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Ring-Trip Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Test Circuits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Le79R79 Test Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Application Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Physical Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
32-pin PLCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
32-pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Revision B to C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Revision C to D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Revision D to E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Revision E to F . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Revision F to G . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Revision G to H . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Revision H to I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Revision I to J1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Revision J1 to K1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Revision K1 to L1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Revision L1 to M1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
2
Le79R79 VE580 Series Data Sheet
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, overvoltage 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 linecard 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 Am79C02/03/031 DSLAC™ device, the Am79Q02/
021/03 Programmable Quad SLAC (QSLAC™) device, or the Am79Q5457/4457 Nonprogrammable QSLAC device.
The Le79R79 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, fiber-in-the-loop, radio-in-the-loop, hybrid fiber/coax and video telephony (home-
side) boxes. The Le79R79 Ringing SLIC can provide sufficient voltage to meet the stringent LSSGR five-ringer equivalent
specification. Using a CMOS-compatible input waveform and wave shaping R-C network, the Le79R79 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 Le79R79 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 device automatically switches to a higher
voltage in the On-hook (Standby) state.
Like all of the Legerity SLIC devices, the Le79R79 Ringing SLIC device supports on-hook transmission, ring-trip detection,
programmable loop-detect threshold, and is available with on-chip polarity reversal. The Le79R79 Ringing SLIC device is a
programmable constant-current feed device with two on-chip relay drivers to operate external relays. Several performance
grades are available to meet both CCITT and LSSGR requirements, including various longitudinal balance options.
Figure 1.
Le79R79 Block Diagram
Relay Driver
RTRIP1
RTRIP2
Relay Driver
A(TIP)
Ring-Trip
Detector
HPA
Two-Wire
Interface
HPB
Signal
Transmission
B(RING)
Power-Feed
Controller
Ground-Key
Detector
Off-Hook
Detector
Input Decoder
and Control
RYOUT2
RYE
RYOUT1
D1
D2
C1
C2
C3
E1
DET
RD
VTX
RSN
RINGIN
RDC
RDCR
VBAT2
RSGL
Switch
Driver
VBAT1
VCC VNEG BGND
AGND/DGND
RSGH
B2EN
Le79R79 VE580 Series Data Sheet
3
CONNECTION DIAGRAMS
RYOUT2
B(RING)
32
VBAT2
BGND
A(TIP)
31
VCC
4
3
2
1
RYE
RYOUT1
B2EN
VBAT1
D1
E1
C3
C2
DET
RD
30
29
28
27
26
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
RTRIP1
RTRIP2
HPB
HPA
RINGIN
RDCR
VTX
VNEG
RSN
32-pin PLCC
25
24
23
22
21
C1
D2
NC
RSGH
RSGL
RDC
RYOUT2
AGND/DGND
26
RYE
RYOUT1
B2EN
VBAT1
D1
E1
C3
C2
32
1
2
3
4
31
30
29
28
AX
27
RD
BX
Top View
RTRIP1
25
24
23
22
21
VBAT2
BGND
VCC
RTRIP2
HPB
HPA
RINGIN
RDCR
VTX
VNEG
RSN
32-pin QFN
5
6
7
8
9
10
11
12
13
14
15
EXPOSED PAD
20
19
18
17
16
DET
C1
D2
RSGH
Note:
1.
2.
3.
Pin 1 is marked for orientation.
NC = No connect.
The thermally enhanced QFN package features an exposed pad on the underside which must be electrically tied to VBAT1.
4
Le79R79 VE580 Series Data Sheet
AGND
RSGL
RDC
NC
PIN DESCRIPTIONS
Pin Names
AGND/DGND
A(TIP)
B2EN
BGND
B(RING)
C3–C1
D1
D2
DET
E1
HPA
HPB
NC
RD
RDC
RDCR
RINGIN
RSGH
RSGL
Type
Ground
Output
Input
Ground
Output
Input
Input
Input
Output
Input
Capacitor
Capacitor
—
Resistor
Output
—
Input
Input
Input
Analog and digital ground
Output of A(TIP) power amplifier
V
BAT2
Enable. Logic Low enables operation from V
BAT2
. Logic High enables operation from V
BAT1
. TTL
compatible.
Battery (power) ground
Output of B(RING) power amplifier
Decoder. SLIC control pins. C3 is MSB and C1 is LSB. TTL compatible.
Relay1 Control. TTL compatible. Logic Low activates the Relay1 relay driver.
Relay2 Control. (Option) TTL compatible. Logic Low activates the Relay2 relay driver.
Hook switch detector. When enabled, a logic Low indicates that the selected detector is tripped. The logic
inputs C3–C1 and E1 select the detector. The output is open collector with a built-in 15 kΩ pull-up resistor.
Ground-Key Enable. (Option) A logic High selects the off-hook detector. A logic Low selects the ground-
key detector. TTL compatible.
High-Pass Filter. A(TIP) side of high-pass filter capacitor.
High-Pass Filter. B(RING) side of high-pass filter capacitor.
Not internally connected.
Detect Resistor. Detector threshold set and filter pin.
DC Feed Resistor. Connection point for the DC-feed current programming network. The other end of the
network connects to the receiver summing node (RSN). The sign of V
RDC
is negative for normal polarity
and positive for reverse polarity.
Connection point for feedback during ringing.
Ring Signal. Pin for ring signal input. Square-wave shaped by external RC filter. Requires 50% duty cycle.
CMOS-compatible input.
Saturation Guard High. Pin for resistor to adjust Open Circuit voltage when operating from V
BAT1
.
Saturation Guard Low. Pin for resistor to adjust the anti-saturation cut-in voltage when operating from
both V
BAT1 and
V
BAT2
.
Receive Summing Node. The metallic current (both 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.
Ring-Trip Detector. Ring-trip detector threshold set and filter pin.
Ring-Trip Detector. Ring-trip detector threshold offset (switch to V
BAT1
). For power conservation in any
nonringing state, this switch is open.
Common Emitter of RYOUT1/RYOUT2. Emitter output of RYOUT1 and RYOUT2. Normally connected to
relay ground.
Relay/Switch Driver. Open collector driver with emitter internally connected to RYE.
Relay/Switch Driver. (Option) Open collector driver with emitter internally connected to RYE.
Battery supply and connection to substrate.
Power supply to output amplifiers. Connect to off-hook battery through a diode.
Positive analog power supply
Negative analog power supply. This pin is the return for the internal V
EE
regulator.
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.
Description
RSN
RTRIP1
RTRIP2
RYE
RYOUT1
RYOUT2
VBAT1
VBAT2
VCC
VNEG
VTX
Input
Input
Input
Output
Output
Output
Battery
Battery
Power
Power
Output
Le79R79 VE580 Series Data Sheet
5
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