Description

The T7502 device is a single-chip, two-channel A-law PCM codec with filters. This integrated circuit provides analog-to-digital and digital-to-analog conversion. It provides the transmit and receive filtering necessary to interface a voice telephone circuit to a time-division multiplexed (TDM) system. The device features a differential transmit amplifier, and the power receive amplifier is capable of driving 600 Ω differentially. PCM timing is defined by a single frame sync pulse. This device operates in a delayed timing mode (digital data is valid one clock cycle after frame sync goes high). The T7502 is packaged in a 20-pin SOJ.

Features

■ +5 V only

■ Automatic powerdown mode

■ Low-power, latch-up-free CMOS technology

■ On-chip sample and hold, autozero, and precision voltage reference

■ Differential architecture for high noise immunity and power supply rejection

■ Automatic master clock frequency selection

■ 2.048 MHz or 4.096 MHz fixed data rate

■ Frame sync controlled channel swapping

■ Differential analog I/O

■ 300 Ω output drivers

■ Operating temperature range: –40 °C to +85 °C

■ A-law companding

Applications

■ Speakerphone

■ Telephone answering device (TAD)

■ POTS for ISDN