Am79M576A
Metering Subscriber Line Interface Circuit
DISTINCTIVE CHARACTERISTICS
s
Programmable constant-resistance feed
s
Programmable loop-detect threshold
s
Ground-key detect
s
Performs polarity reversal
s
Ring relay driver
s
Supports 2.2 Vrms metering (12 and 16 kHz)
s
Line feed characteristics independent of battery
variations
s
On-chip switching regulator for low-power
dissipation
s
Two-wire impedance set by single external
impedance
s
Tip Open state for ground-start lines
s
On-hook transmission
BLOCK DIAGRAM
A(TIP)
Ring Relay
Driver
Ground-Key
Detector
Input Decoder
and Control
VCCRING
RINGOUT/DGND
C1
C2
C3
E0
E1
HPB
Two-Wire
Interface
DET
Signal
Transmission
VTX
RSN
HPA
B(RING)
Off-Hook Detector
RD
Power-Feed
Controller
RDC
DA
DB
VREG
L
VBAT
BGND
Ring-Trip
Detector
Switching
Regulator
CHS QBAT CHCLK
VCC
VEE
AGND/DGND
Publication#
18412
Rev:
D
Amendment: /0
Issue Date:
October 1999
ORDERING INFORMATION
Standard Products
AMD standard products are available in several packages and operating ranges. The order number (Valid Combination) is
formed by a combination of the elements below.
Am79M576A
J
C
TEMPERATURE RANGE
C = Commercial (0°C to 70°C)*
PACKAGE TYPE
J = 32-pin Plastic Leaded Chip Carrier (PL 032)
PERFORMANCE GRADE
Blank = Standard Specification
–1 = Performance Grading
–2 = Performance Grading
DEVICE NUMBER/DESCRIPTION
Am79M576A
Metering Subscriber Line Interface Circuit
Valid Combinations
–1
–2
JC
Am79M576A
Valid Combinations
Valid Combinations list configurations planned to
be supported in volume for this device. Consult
the local AMD sales office to confirm availability
of specific valid combinations, to check on newly
released combinations, and to obtain additional
data on AMD’s standard military grade products.
Note:
* Functionality of the device from 0°C to +70°C is guaranteed by production testing. Performance from –40°C to +85°C is
guaranteed by characterization and periodic sampling of production units.
2
Am79M576A Data Sheet
CONNECTION DIAGRAM
Top View
32-Pin PLCC
RINGOUT/DGND
B(RING)
VCC
A(TIP)
31
BGND
VREG
4
TP
VCCRING
L
VBAT
QBAT
CHS
CHCLK
RSVD
E1
5
6
7
8
9
10
11
12
13
14
E0
3
2
1
32
30
29
28
27
26
25
24
23
22
21
TP
DA
RD
HPB
HPA
VTX
VEE
RSN
AGND
15
DET
16
C2
17 18
C1
C3
19 20
DGND
RDC
Notes:
1. Pin 1 is marked for orientation.
2. TP is a thermal conduction pin tied to substrate.
3. RSVD = Reserved. Do not connect to this pin.
SLIC Products
DB
3
PIN DESCRIPTIONS
Pin Names
AGND
A(TIP)
BGND
B(RING)
C3–C1
CHCLK
CHS
DA
DB
DET
DGND
E0
E1
HPA
HPB
L
Type
Gnd
Output
Gnd
Output
Input
Input
Input
Input
Input
Output
Gnd
Input
Input
Capacitor
Capacitor
Output
Analog (quiet) ground
Output of A(TIP) power amplifier
Battery (power) ground
Output of B(RING) power amplifier
Decoder. TTL compatible. C3 is MSB and C1 is LSB.
Chopper clock. Input to switching regulator (TTL compatible). Freq = 256 kHz (Nominal).
Chopper Stabilization. Connection for external stabilization components.
Ring-trip negative. Negative input to ring-trip comparator.
Ring-trip positive. Positive input to ring-trip comparator.
Detector. When enabled, a logic Low indicates that the selected detector is tripped. Logic inputs
C3–C1, E1, and E0 select the detector. Open-collector with a built-in 15 kΩ pull-up resistor.
Digital ground
A logic High enables DET. A logic Low disables DET.
Ground-key enable. E1 = High connects the ground-key detector to DET, and E1 = Low connects
the off-hook or ring-trip detector to DET.
High-pass filter capacitor. A(TIP) side of high-pass filter capacitor.
High-pass filter capacitor. B(RING) side of high-pass filter capacitor.
Switching Regulator Power Transistor. Connection point for filter inductor and anode of catch
diode. Has up to 60 V of pulse waveform and must be isolated from sensitive circuits. Keep the
diode connections short because of the high currents and high di/dt.
Quiet Battery. Filtered battery supply for the signal processing circuits.
Detector resistor. Threshold modification and filter point for the off-hook detector.
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.
Relay ground for 5 V relays—externally connected to DGND.
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 current all
connect to this node.
Thermal pin. Connection for heat dissipation. Internally connected to substrate (QBAT). Leave as
open circuit or connected to QBAT. In both cases, the TP pins can connect to an area of copper
on the board to enhance heat dissipation.
Battery supply
+5 V power supply
Ring relay driver (sinks current to RINGOUT).
–5 V power supply
Regulated Voltage. Provides negative power supply for power amplifiers, connection point for
inductor, filter capacitor, and chopper stabilization.
Transmit Audio. This output is 0.510 times the A(TIP) and B(RING) metallic voltage.The other end
of the two-wire input impedance programming network connects here.
Description
QBAT
RD
RDC
Battery
Resistor
Resistor
RINGOUT/
DGND
RSN
Output
Input
TP
Thermal
VBAT
VCC
VCCRING
VEE
VREG
VTX
Battery
Power
Input
Power
Input
Output
4
Am79M576A Data Sheet
ABSOLUTE MAXIMUM RATINGS
Storage temperature ......................... –55
°
C to +150
°
C
Ambient temperature, operating ........... –0
°
C to +70
°
C
V
CC
with respect to AGND ................. –0.4 V to +7.0 V
V
EE
with respect to AGND ................. +0.4 V to –7.0 V
V
BAT
with respect to AGND ................ +0.4 V to –70 V
Note:
Rise time of V
BAT
(dv/dt) must be limited to 27 V/µs or
less when Q
BAT
bypass is 0.33
µF.
OPERATING RANGES
Commercial (C) Devices
Ambient temperature ............................. 0
°
C to +70
°
C*
V
CC
..................................................... 4.75 V to 5.25 V
V
EE
................................................. –4.75 V to –5.25 V
V
BAT
.................................................. –46.4 V to –54 V
V
CC
RING ................................................. 0 V to 5.25 V
AGND/DGND.......................................................... 0 V
BGND with respect to AGND.................... –2 V to +2 V
Load resistance on VTX to ground .............. 10 k
Ω
min
Operating Ranges define those limits between which device
functionality is guaranteed.
* Functionality of the device from 0°C to +70°C is guaranteed
by production testing. Performance from –40°C to +85°C is
guaranteed by characterization and periodic sampling of
production units.
BGND with respect to AGND/DGND.. +1.0 V to –3.0 V
A(TIP) or B(RING) to BGND:
Continuous ......................................... –70 V to +2 V
10 ms (f = 0.1 Hz) ............................... –70 V to +5 V
1
µ
s (f = 0.1 Hz) ................................ –90 V to +10 V
250 ns (f = 0.1 Hz) .......................... –120 V to +15 V
Current from A(TIP) or B(RING)
....................... ±
150 mA
Voltage on VCCRING ........................... –0.3 V to +7 V
Current through relay drivers or
internal driver catch diodes ..............................60 mA
Voltage on ring-trip inputs DA and DB .......V
BAT
to 0 V
Current into ring-trip inputs
.................................. ±
10 mA
Peak current into regulator switch (L pin) ........150 mA
Switcher transient peak off voltage on L pin ......+1.0 V
C3–C1, E0, E1, CHCLK
to AGND...................................–0.4 V to V
CC
+ 0.4 V
Maximum power dissipation (see note) ....... T
A
= 70
°
C
In 32-pin PLCC package..................................1.2 W
Note:
Thermal limiting circuitry on-chip will shut down the
circuit at a junction temperature of about 165°C. The de-
vice should never be exposed to this temperature. Opera-
tion above 145°C junction temperature may degrade
device reliability. See the SLIC Packaging Considerations
for more information.
Stresses above those listed under Absolute Maximum Ratings
may cause permanent device failure. Functionality at or above
these limits is not implied. Exposure to Absolute Maximum
Ratings for extended periods may affect device reliability.
SLIC Products
5
MCU
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