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Octal, E1 Analog Front End

The CS61881 contains eight analog front ends that each provide the line interface for E1 transmission systems. The device contains eight receivers and transmitters supporting a 2.048 Mbps data rate compliant to ITU G.703. This device is commonly used with external circuitry that supplies data encoding/decoding, clock recovery, and jitter attenuation.

The CS61881 makes use of ultra-low power, matched impedance transmitters with controls for independent power down and tristate that reduce power beyond that achieved by traditional driver designs. By achieving a more precise line match, this technique also provides superior return loss characteristics, exceeding ETS 300 166. The internal line matching circuitry reduces the external component count and eliminates the need to change components to support both 75 and 120 watt lines.

The receiver has a high noise margin, providing reliable data recovery even with cable attenuation of over 12 dB. It has an impedance matched front end, eliminating the need to change components to support both 75 watt and 120 watt line impedances. The receiver also incorporates LOS detection that is compliant to the most recent specifications.

Product Features
  • Octal E1 line interface unit compliant with G.703
  • No external component changes for 120 W/75 W
  • Analog LOS detection per ITU G.775
  • Transmitter short circuit current limiter (<50mA)
  • TX drivers with fast tristate and power-down
  • Transmit return loss exceeds ETS 300 166
  • JTAG boundary scan compliant to IEEE 1149.1
  • 5-wire JTAG interface for improved diagnostics and reduced manufacturing cost
  • Single supply 3.3V operation, 5V tolerant I/O
  • Very low power <100 mW per channel
  • Package: 144-pin LQFP, 160 BGA

Documents
CS61881 Product
Data Sheet

APR '00, DS451PP3 : 462 Kb
CDB61881 Evalua
tion Board Data Sheet

JAN '01, DS451DB1 : 99 Kb
Errata: CS61881 Revisi
on A

APR '00, ER451A1 : 7 Kb
Errata: CDB61881 Revis
ion B

JAN '01, ER451B1 : 21 Kb

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Copyright © 2002 Cirrus Logic Inc.