1/28

October 2001

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)

1 & 2) OR BITSTREAM INTERFACE

INTERFACE (LITTLE AND BIG ENDIAN

COMPATIBILITY)

LATENCY

PATHS:

FAST

AND

INTERLEAVED

(CELL DELINEATION, CELL INSERTION,

HEC)

CARRIERS

ROTOR AND ADAPTATIVE FREQUENCY

DOMAIN EQUALIZING

µm HCMOS7 TECHNOLOGY

APPLICATIONS

Routers at SOHO, stand-alone modems, PC

modems.

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.

The ST70235A can be split up into two different

sections.

The

physical

one

performs

the

DMT modulation, demodulation, Reed-Solomon

encoding, bit interleaving and 4D trellis coding.

The ATM section embodies framing functions for

the generic and ATM Transmission Convergence

(TC) layers. The generic TC consists of data

scrambling and Reed Solomon error corrections,

with and without interleaving.

The ST70235A is controlled and programmed

by an external controller (ADSL Transceiver Con-

troller, ATC) that sets the programmable coeffi-

cients. The firmware controls the initialization

phase and carries out the consequent adaptation

operations.

TQFP144 Full Plastic

(20 x 20 x 1.40 mm)

ORDER CODE: ST70235A

ST70235A

This is advance information on a new product now in development or undergoing evaluation. Details are subject to change without notice.

PRELIMINARY DATA