am79m576a Advanced Micro Devices, am79m576a Datasheet - Page 4

• Manufacturer Part Number: am79m576a
• Description: Metering Subscriber Line Interface Circuit
• Manufacturer: Advanced Micro Devices

PIN DESCRIPTIONS
4
AGND
A(TIP)
BGND
B(RING)
C3–C1
CHCLK
CHS
DA
DB
DET
DGND
E0
E1
HPA
HPB
L
QBAT
RD
RDC
RINGOUT/
DGND
RSN
TP
VBAT
VCC
VCCRING
VEE
VREG
VTX
Pin Names
Gnd
Output
Gnd
Output
Input
Input
Input
Input
Output
Gnd
Input
Input
Capacitor
Capacitor
Output
Battery
Resistor
Output
Input
Thermal
Battery
Power
Input
Power
Input
Output
Input
Resistor
Type
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 k 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
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.
Am79M576A Data Sheet
Description
RDC
is negative for normal polarity and positive