am79514 Advanced Micro Devices, am79514 Datasheet - Page 4

• Manufacturer Part Number: am79514
• Description: Subscriber Line Interface Circuit
• Manufacturer: Advanced Micro Devices

PIN DESCRIPTIONS
4
Pin Names
RINGOUT
TESTOUT
B(RING)
CHCLK
C3–C1
DGND
AGND
A(TIP)
BGND
VREG
QBAT
VBAT
CHS
RDC
RSN
VCC
DET
HPA
HPB
VEE
VTX
RD
C4
DA
DB
TP
E0
E1
L
Capacitor
Capacitor
Resistor
Resistor
Thermal
Battery
Battery
Output
Output
Output
Output
Output
Output
Output
Type
Power
Power
Inputs
Input
Input
Input
Input
Input
Input
Input
Input
Input
Gnd
Gnd
Gnd
Ring relay driver. Sourcing from BGND with internal diode to QBAT.
Analog 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 High enables the driver.
Digital ground.
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. The detector
is selected by the logic inputs (C3–C1 and E1). The output is open-collector with a built-in 15 k
pull-up resistor.
Read enable. 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.
This pin will have up to 60 V of pulse waveform on it and must be isolated from sensitive circuits.
Extreme care must be taken to keep the diode connections short because of the high currents and
high di/dt.
Quiet battery. Filtered battery supply for the signal processing circuits. An external 100 , 1/8
resistor must be connected between QBAT and VBAT pins.
Detect 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). The sign of V
mal polarity and positive for reverse polarity.
Receive summing node. The metallic current (both AC and DC) between A(TIP) and B(RING) is
equal to 1000 times 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. Care should
be taken to 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.
+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 a unity gain version of the A(TIP) and B(RING) metallic voltage. The
other end of the two-wire input impedance programming network connects here.
Am79514 Data Sheet
Description
RDC
is negative for nor-