AM79M574-1JC ETC2 [List of Unclassifed Manufacturers], AM79M574-1JC Datasheet - Page 4

• Manufacturer Part Number: AM79M574-1JC
• Description: Metering Subscriber Line Interface Circuit
• Manufacturer: ETC2 [List of Unclassifed Manufacturers]

PIN DESCRIPTIONS
4
AGND
A(TIP)
BGND
B(RING)
C3–C1
C4
CHCLK
CHS
DA
DB
DET
DGND
E0
E1
HPA
HPB
L
QBAT
RD
RDC
RINGOUT
RSN
TESTOUT
TP
VBAT
VCC
VEE
VREG
VTX
Pin Names
Gnd
Output
Gnd
Output
Input
Input
Input
Input
Input
Input
Output
Gnd
Input
Input
Capacitor
Capacitor
Output
Battery
Resistor
Resistor
Output
Input
Output
Thermal
Battery
Power
Power
Input
Output
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.
Test relay driver command. TTL compatible. A logic Low enables the driver.
Chopper clock. Input to switching regulator (TTL compatible). Frequency = 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
Read Enable. A logic High enables DET. A logic Low disables DET.
Ground enable. When E0 is High, 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 resistance programming network, which
also connects to the Receiver Summing Node (RSN). V
positive for reverse polarity.
Ring relay driver. Sourcing from BGND with internal diode to QBAT.
Receive Summing Node. The metallic current (AC and DC) between A(TIP) and B(RING) =
1000 x the current into this pin. The networks that program receive gain, two-wire
impedance, and feed resistance all connect to this node. This node is extremely sensitive.
Route the 256 kHz chopper clock and switch lines away from the RSN node.
Test relay driver. Sourcing from BGND with internal diode to QBAT.
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. Connected to office battery supply through an external protection diode.
+5 V power supply
–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.
Am79M574 Data Sheet
Description
RDC
is negative for normal polarity and