ATM Interface and Framer IC
for ADSL Chipsets
a
AD6438-2
FEATURES
GENERAL DESCRIPTION
Component in Analog Devices’ AD20msp918 ADSL
Chipset
Suitable for CO (Central Office) or Residence (ATU-R
and ATU-C)
Designed to ANSI T1.413 Issue 2, ETSI TR238, ITU
G.992.1 and G.992.2 Standards
ATM Operation and Functionality as Defined by Issue 2
ATM Mode and ADSL Forum
Optional Serial Interface to Access the PMD Sublayer,
Available on the AD6438-2, Not Available on the AD6438
UTOPIA Level 1 and Level 2 Physical Interface
Byte-Parallel or “Multi-PHY” for Dual Latency
Implements Both Issue 1 and Issue 2 ADSL Framing
Structure (Reduced Overhead)
The AD6438-2 Interface and Framer IC is part of Analog Devices’
AD20msp918 chipset, a flexible standards-based solution for
creating high-performance, ATM-based, ADSL modems. The
AD6438-2 is interoperable with the AD20msp910 ADSL chipset.
The AD6438-2 interfaces an ADSL modem to an external sys-
tem, at either CO (Central Office) or RT (Remote Terminal)
modem, using a standard UTOPIA 1- or 2-port (byte-wide, Cell
or Byte Mode). It inserts ATM cells into an ADSL line, with
functions that correspond to the Transmission Convergence
(TC) sublayer in the BISDN protocol reference model (per
ITU-T I.432 and T1.413 Issue 2). These include cell delinea-
tion, HEC generation, and cell-rate adaption, as defined by the
ATM working group of the ADSL Forum and the RBB working
group of the ATM Forum.
144-Lead LQFP
The AD6438-2 implements both standard and reduced-overhead
framing per ANSI T1.413 Issue 2, and includes FEC (Forward
Error-Correcting) Code and interleaving.
–40؇C to +85؇C, 3.3 V Operation
FUNCTIONAL BLOCK DIAGRAM
35MHz SYSTEM
AD6438-2
TIMING
OFFSET
NTR
8kHz
NTR
FAST
F
ADSL
Tx
Rx
FRAMER
ATM
UTOPIA 1/2
INTERFACE
FEC
AD6439-2
I
INTLV
ISSUE
1, 2
ADDR
CONTROL
ADDRESS
CONTROL
D
A
ADTSP-2183
INTERLEAVE RAM
REV. 0
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
Fax: 781/326-8703
World Wide Web Site: http://www.analog.com
© Analog Devices, Inc., 2000