TP3076

and Digital Phone Applications

General Description

The TP3076 is a second-generation combined PCM CODEC

and Filter devices optimized for digital switching applications

on subscriber line and trunk cards and digital phone applica-

tions. Using advanced switched capacitor techniques,

COMBO II combines transmit bandpass and receive low-

pass channel filters with a companding PCM encoder and

decoder. The devices are A-law and µ-law selectable and

employ a conventional serial PCM interface capable of being

clocked up to 4.096 MHz. A number of programmable func-

tions may be controlled via a serial control port.

Channel gains are programmable over a 25.4 dB range in

each direction.

To enable COMBO II to interface to the SLIC control leads, a

number of programmable latches are included; each may be

configured as either an input or an output. The TP3076 pro-

vides 4 latches.

Features

n Complete CODEC and Filter system including:

— Transmit and receive PCM channel filters

— µ-law or A-law companding coder and decoder

— Receive power amplifier drives 300

Ω

— 4.096 MHz serial PCM data (max)

n Programmable functions:

— Transmit gain: 25.4 dB range, 0.1 dB steps

— Receive gain: 25.4 dB range, 0.1 dB steps

— Time-slot assignment; to 64 slots/frame

— 4 interface latches

— A or µ-law

— Analog loopback

— Digital loopback

n Direct interface to solid-state SLICs

n Standard serial control interface

n 80 mW operating power (typ)

n 1.5 mW standby power (typ)

n Designed for CCITT and LSSGR specifications

n TTL and CMOS compatible digital interfaces

Note: See also AN-614 COMBO II application guide.

Block Diagram

DS009758-1

FIGURE 1.

April 1994

© 1999 National Semiconductor Corporation

DS009758

www.national.com