am79m535 Advanced Micro Devices, am79m535 Datasheet - Page 4

• Manufacturer Part Number: am79m535
• Description: Metering Subscriber Line Interface Circuit
• Manufacturer: Advanced Micro Devices

PIN DESCRIPTIONS
4
AGND
DGND
A(TIP)
BGND
B(RING)
C3–C1
CHCLK
CHS
DA
DB
DET
E0
E1
GKFIL
HPA
HPB
L
QBAT
RD
RDC
RINGOUT
RSN
TP
VBAT
VCC
VEE
VREG
VTX
Pin Names
Gnd
Gnd
Output
Gnd
Output
Input
Input
Input
Input
Input
Output
Input
Input
Capacitor
Capacitor
Capacitor
Output
Battery
Resistor
Resistor
Output
Input
Thermal
Battery
Power
Power
Input
Output
Type
Analog (quiet) ground
Digital 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, 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.
Read Enable. A logic Low disables DET. A logic High enables DET.
Ground-Key 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.
Ground-Key Filter Capacitor Connection. An external capacitor for filtering out high-
frequency noise from the ground-key loop can be connected to this pin. An internal
36 k –20%, +40% resistor is provided to form an RC filter with the external capacitor.
In versions which have a GKFIL pin, a 3.3 nF minimum capacitance must be
connected from the GKFIL pin to ground.
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 on it 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. The
other end of the network connects to the Receiver Summing Node (RSN). V
negative for normal polarity and positive for reverse polarity.
Ring Relay Driver. Sourcing from BGND with internal diode to Q
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. This node is extremely sensitive. Route the 256 kHz
chopper clock and switch lines away from the RSN 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.
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. VTX
also sources the two-wire input impedance programming network.
Am79M535 Data Sheet
Description
BAT
.
RDC
is