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