
Advance Data Sheet
October 2000
T8538A Quad Programmable Codec
Features
I
3.3 V operation
I
Per-channel programmable gains, equalization,
termination impedance, and hybrid balance
I
Programmable
μ
-law, linear, or A-law modes
— Up to 256 time slots per frame
— Supports PCM data rates of 512 kbits/s to
16.384 Mbits/s
— Double-clock mode timing compatible with
ISDN standard interfaces
I
Fully programmable time-slot assignment with bit
offset
I
Analog and digital loopback test modes
I
Serial microprocessor interface
— Normal and byte-by-byte control modes
— Fast scan mode
I
Six bidirectional control leads per channel, for
SLIC and line card function control
I
Differential analog output
— Mates directly to SLICs, eliminating external
components
I
Sigma-delta converters with dither noise reduction
I
Quad design to minimize package count on dense
line card applications
I
Meets or exceeds ITU-T G.711—G.712 and rele-
vant
Telcordia Technologies
* requirements
* Telcordia Technologiesis a trademark of Bell Communications
Research, Inc.
Description
The device consists of four independent channels of
codec and digital signal processing functions on one
chip. In addition to the classic A-to-D and D-to-A con-
version, each channel provides termination imped-
ance synthesis and a hybrid balance network.
The device is controlled by a serial microprocessor
interface, and a series of bidirectional I/O leads are
provided so that this control mechanism can be uti-
lized to operate the battery feed device, ringing volt-
age switches, etc. Common data and clock paths can
be shared over any number of devices. All the filter
coefficients, signal processing, SLIC, and test fea-
tures are accessible through this interface. This
serial interface can be operated at speeds up to
16 Mbits/s.
The choice of a PCM bus is also programmable, with
any channel capable of being assigned to any time
slot. The PCM bus can be operated at speeds up to
16.384 Mbits/s, allowing for a maximum of 256 time
slots. Separate transmit and receive interfaces are
available for 4-wire bus designs, or they can be
strapped together for a 2-wire PCM bus.
The device is available in two packages.
The T8538A 64-pin TQFP features five data latches
per channel.
The T8538A 100-pin TQFP features six data latches
per channel.
The T8538A and the T8539A Quad Programmable
Line Card Signal Processor with Echo Cancellation
are pin compatible.