Description

The Lucent Technologies Microelectronics Group T7264 U-Interface 2B1Q Transceiver integrated circuit provides full-duplex, basic-rate (2B+D) integrated services digital network (ISDN) communications on a 2-wire digital subscriber loop at either the LT or NT and conforms to the ANSI North American Standard T1.601-1992. The single +5 V CMOS device is packaged in a 44-pin plastic leaded chip carrier (PLCC).

Features

■ U-interface 2B1Q transceiver

— Range over 18 kft on 26 AWG

— ISDN basic-rate 2B+D

— Full-duplex, 2-wire operation

— 2B1Q four-level line code

— Conforms to ANSI North American Standard T1.601-1992

— Supports NT quiet mode and insertion loss test mode for maintenance

■ K2 interface

— 2B+D data

— 512 kbits/s TDM interface

— Frame and superframe markers

— Embedded operations channel (eoc)

— U-interface M bits and crc results

— Device control and status

■ Other

— Single +5 V (±5) supply

— –40 °C to +85 °C

— 44-pin PLCC

■ Power consumption

— Operating 275 mW typical

— Idle mode 30 mW typical

■ Analog front end

— On-chip line driver for 2.5 V pulses

— On-chip balance network

— Sigma-delta A/D converter

— Internal 15.36 MHz crystal oscillator

— Supports 15.36 MHz external clock input

■ Digital signal processor

— Digital timing recovery (pull range ±250 ppm)

— Echo cancellation (linear and nonlinear)

— Accommodates distortion from bridged taps

— Scrambling/descrambling

— crc calculations

— Selectable LT or NT operation

— Start-up sequencing with timers

— Activation/deactivation support

— Cold start in 3.5 seconds (typical)

— Warm start in 200 ms (typical)

— U-frame formatting and decoding