AM79C03 AMD [Advanced Micro Devices], AM79C03 Datasheet - Page 8

• Manufacturer Part Number: AM79C03
• Description: Dual Subscriber Line Audio Processing Circuit (DSLAC) Devices
• Manufacturer: AMD [Advanced Micro Devices]

Power supply for the Am79C02:
AGND
AGND
DGND
DGND
PGND
VCCA
VCCA
VCCD
VCCD
VCCP
VEE
VEE
Power supply for the Am79C03 and Am79C031:
AGND
DGND
VCCA
VCCD
VEE
VEE
The many separate power supply inputs are intended to
provide for good power supply decoupling techniques.
Note that all of the +5 V inputs should be connected to
the same source, all of the ground inputs should be con-
nected to the same source, and both of the –5 V inputs
should be connected to the same source.
8
1
2
1
2
1
2
1
2
1
2
1
2
Analog Ground (Channel 1)
Analog Ground (Channel 2)
Digital Ground (Channel 1)
Digital Ground (Channel 2)
PCM I/O Ground
+5 V Analog Power Supply (Channel 1)
+5 V Analog Power Supply (Channel 2)
+5 V Digital Power Supply
Internally connected to substrate
+5 V Digital Power Supply
Internally connected to substrate
+5 V PCM I/O Power Supply
Internally connected to substrate
–5 V Power Supply (Channel 1)
–5 V Power Supply (Channel 2)
Analog Ground
Digital Ground
+5 V Analog Power Supply
+5 V Digital Power Supply
Internally connected to substrate
–5 V Power Supply (Channel 1)
–5 V Power Supply (Channel 2)
Am79C02/03/031(A) Data Sheet
FUNCTIONAL DESCRIPTION
The DSLAC device performs the codec/filter functions
associated with the four-wire section of the subscriber
line circuitry in a digital switch. These functions involve
converting an analog voice signal into digital PCM sam-
ples and converting digital PCM samples back into an
analog signal. During conversion, digital filters are used
to bandlimit the voice signals.
Independent channels allow the DSLAC device to func-
tion as two SLAC devices. All of the digital filtering is
performed in digital signal processors operating from
either a 2.048 MHz or 4.096 MHz external clock. The
A/D, D/A, and signal processing is separate for each
channel and each channel has its own Chip Select (CS1
and CS2) to allow separate programming.
The user-programmable filters set the receive and
transmit gain, perform the transhybrid balancing func-
tion, permit adjustment of the two-wire termination im-
pedance, and provide equalization of the receive and
transmit paths. All programmable digital filter coeffi-
cients can be calculated using the AmSLAC2 software.
The PCM codes can be either 8-bit companded A-law
or µ-law. The PCM data is read and written to the
PCM highway in user-programmable time slots at
rates of 128 kHz to 8.192 MHz. The output hold time
and the transmit clock edge can be selected for com-
patibility with other devices that can be connected to
the PCM highway.
Four configurations of the DSLAC device are offered
with the PCM interface described above. The
Am79C02(A), the original version of the DSLAC device,
is available in the 44-pin PLCC package. The
Am79C03(A) and Am79C031(A) are reduced pin count
versions obtained by consolidating a number of ground
and power supply buses on chip, and eliminating the
hardware reset function. The Am79C03(A) is available
in 32-pin PLCC packages. The Am79C031(A) is avail-
able in a 32-pin PLCC package. The “A” version of both
devices (e.g., Am79C02A) offers the adaptive transhy-
brid balance feature described in the Adaptive B Filter
overview.