General Description

The quad programmable line card signal processor 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 conversion, the device includes termination impedance synthesis and a 64-tap echo canceller, functionally, on a perchannel basis. The device is capable of meeting all international standards for terminating impedance and digital encoding format. The processing circuitry for the adjustment of the transmit level (equalization) to accommodate current-sensing SLICs is also included.

Features

■ Includes codec, termination impedance, and echo canceller in one device for line card applications

■ Programmable µ-law, linear, or A-law PCM input and output (ITU-T G.712 compliant)

■ Per-channel programmable gains

■ Per-channel programmable internal termination impedance

■ Per-channel 64-tap echo canceller (ITU-T G.168 compliant)

■ Fully programmable time-slot assignment

■ Analog and digital loopback test modes

■ Serial microprocessor interface

■ Sigma-delta converters with dither to reduce noise

■ Six per-channel, bidirectional control pins for SLIC and line card function control (68-pin package)

■ Quad design to minimize package count on dense line card applications

■ Built-in level correction (transmit equalization) to accommodate current-sensing SLICs

■ Single 5 V operation

■ Available in 68-pin, 64-pin, and 44-pin packages