Controller-less, Scalable, Discrete Multitone-based, G.dmt- and G.lite-
compliant, ADSL Modem Device Set for PCI Applications
Conexant’s AccessRunner ADSL modem device set is compliant
with the full-rate ANSI T1.413 Issue 2 and ITU G.dmt (G.992.1)
ADSL standards, and with the splitterless ITU G.lite (G.992.2)
specification. This rate-adaptive solution is designed for controller-
less PCI desktop applications and supports downstream data rates
of up to 8 Mbps and upstream data rates of up to 1 Mbps.
The device set takes advantage of the processing power available
with most new computers by eliminating the need for a separate
microcontroller, resulting in a cost-effective solution suitable for
both G.dmt and G.lite applications. Host-based software provides
support for current industry standards for PPP over AAL5 over
ATM over ADSL and RFC 1483 for Windows 98 and Windows
2000.
The device set, as shown in Figure 1, consists of four chips:
•
•
•
•
PCI bus interface (AccessRunner P46 in a 176-pin TQFP)
DMT-based data pump (AccessRunner 11627 in a 176-pin
TQFP)
Analog front end (AccessRunner 20431 in a 32-pin TQFP)
Line driver (AccessRunner 20441 in a 16-pin SSOP or
32-pin TQFP)
Features
•
Complete controller-less PCI ADSL
solution
•
Compliant with ADSL standards
−
Full-rate ANSI T1.413 Issue 2 and ITU
G.dmt (G.992.1) standards
−
Splitterless ITU G.lite (G.992.2)
specification
•
DMT modulation and demodulation
•
Full-rate adaptive modem
−
Maximum downstream rate of 8 Mbps
−
Maximum upstream rate of 1 Mbps
•
Supports splitterless ADSL
implementation
•
WAN mode support: PPP over AAL5/ATM
over ADSL via Windows 98/2000
•
LAN mode support: RFC 1483 via
Windows 98/2000
•
Compliant with PCI Local Bus
Specification, Revision 2.2
•
Compliant with PCI Bus Power
Management Interface Specification,
Version 1.0
•
Tone detection for low power mode
D20431 AFE Features
PCI Bus
Host-
Based
ADSL
Controller
Software
P46
PCI Bus
Interface
176-pin TQFP
11627
ADSL DMT
Data Pump
176-pin TQFP
20431
Analog Front
End
32-pin TQFP
20441
Line Driver
16-pin TSSOP
Telephone
Line
Figure 1. AccessRunner ADSL Modem for PCI Applications
•
Receive signal path includes:
−
Integrated hybrid receiver circuit with
programmable gain
−
High pass filtering and 27dB of
Automatic Gain Control (AGC) to
improve signal-to-echo ratio
−
14-bit ADC
•
Transmit signal path includes:
−
30dB of AGC for transmit power control
−
Low pass filtering to suppress noise in
the receive band
−
14-bit DAC
Independent digital serial data and control
•
interfaces
Low power tone detection mode.
•
Data Sheet (Preliminary)
Conexant Proprietary Information
Doc. No.100394B
October 19, 1999
AccessRunner
Controller-less ADSL Modem Device Set for PCI Applications
ADSL (Asymmetric Digital Subscriber Line) is a transmission
technology used to carry user data over a single twisted pair line
from the Central Office to the customer premises. The downstream
(Central Office to Customer Premises) direction typically supports
a much higher data rate than the upstream or return (Customer
Premises to Central Office) channel. This asymmetric nature lends
itself to applications like remote LAN access, Internet access, and
video delivery. The downstream data rates can go up to 8 Mbps.
The upstream data rates can go up to 1 Mbps. Actual data rates
depend on the transceiver implementation, loop length,
impairments, and transmitted power.
The Conexant ADSL Modem Device Set for PCI Applications is
based upon a scalable architecture. This architecture will enable
the device set to support an emerging set of ADSL specifications
called G.lite. G.lite is expected to make it possible for telcos to
deploy consumer-oriented, “always on” 1.5 Mbps Internet access
services without the need for splitter equipment or wiring changes
at the customer premises.
D20441 Line Driver Features
•
Differential input and output line driver
•
Thermal shutdown capability
•
Line impedance matching during power-
down
•
Fixed differential gain
11627 ADSL DMT Data Pump
Features
•
Low power (0.5W) consumption
•
DSP-based programmable ADSL data
pump
•
No external Interleave RAM, 16 Kbytes
built-in
•
Single 3.3V
±
5% power supply
•
Echo cancellation
•
Digital interface and rate buffering
•
ADSL framing
•
Forward Error Correction (FEC) encoding
and decoding and interleaving
•
Constellation encoding/decoding
•
IFFT modulation and FFT demodulation
•
Transmit and receive signal digital filtering
•
Time domain equalization
•
Frequency domain equalization
•
Clock recovery
•
CRC and scrambling
•
Digital interface framing
•
ATM mode
•
Bit-synchronous mode
Ordering Information
Product
AccessRunner P46
PCI Bus Interface
AccessRunner 11627
ADSL Discrete Multitone (DMT) Data Pump
AccessRunner 20431
Analog Front End
AccessRunner 20441
Line Driver
Package
176-pin TQFP
176-pin TQFP
32-pin TQFP
16-pin SSOP
32-pin TQFP
Device Number
P46
11627
20431
20441-12
20441-11
Revision History
Revision
A
B
Date
07/09/99
10/19/99
Comments
Initial release
Defined dash numbers and updated figures for 20441 line driver, changed document number from DSL-
015, A
Information provided by Conexant Systems, Inc. is believed to be accurate and reliable. However, no responsibility is assumed by Conexant for its use, nor any
infringement 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 rights of
Conexant other than for circuitry embodied in Conexant products. Conexant reserves the right to change circuitry at any time without notice. This document is
subject to change without notice.
Conexant products are not designed or intended for use in life support appliances, devices, or systems where malfunction of a Conexant product can reasonably be
expected to result in personal injury or death. Conexant customers using or selling Conexant products for use in such applications do so at their own risk and agree
to fully indemnify Conexant for any damages resulting from such improper use or sale.
Conexant, “What's Next in Communications Technologies”, AccessRunner, LANfinity, and the Conexant logo, are trademarks of
Conexant Systems, Inc.
Product names or services listed in this publication are for identification purposes only, and may be trademarks or registered trademarks of their respective
companies. All other marks mentioned herein are the property of their respective owners.
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