GENERAL DESCRIPTION

The ST70235A is the DMT modem and ATM framer of the STMicroelectronics ASCOT™ chipset. When coupled with ST70134 analog front-end and an external controller running dedicated firmware, the product fulfills ANSI T1.413 Issue 2 DMT ADSL specification. The chip supports UTOPIA level 1 and UTOPIA level 2 interface.

■ DMT MODEM FOR CPE ADSL, COMPATIBLE WITH THE FOLLOWING STANDARDS:

- ANSI T1.413 ISSUE 2

- ITU-T G.992.1 (G.DMT)

- ITU-T G.992.2 (G.LITE)

■ SUPPORTS EITHER ATM (UTOPIA LEVEL 1 & 2) OR BITSTREAM INTERFACE

■ 16 BIT MULTIPLEXED MICROPROCESSOR INTERFACE (LITTLE AND BIG ENDIAN COMPATIBILITY)

■ ANALOG FRONT END MANAGEMENT

■ DUAL LATENCY PATHS: FAST AND INTERLEAVED

■ ATM’S PHY LAYER: CELL PROCESSING (CELL DELINEATION, CELL INSERTION, HEC)

■ ADSL’S OVERHEAD MANAGEMENT

■ REED SOLOMON ENCODE/DECODE

■ TRELLIS ENCODE/DECODE (VITERBI)

■ DMT MAPPING / DEMAPPING OVER 256 CARRIERS

■ FINE (2PPM) TIMING RECOVER USING ROTOR AND ADAPTATIVE FREQUENCY DOMAIN EQUALIZING

■ TIME DOMAIN EQUALIZATION

■ FRONT END DIGITAL FILTERS

■ 0.25µm HCMOS7 TECHNOLOGY

■ 144 PIN TQFP

■ POWER CONSUMPTION: 0.4 WATT

APPLICATIONS

Routers at SOHO, stand-alone modems, PC modems.