Sonet transceivers promise best-in-class jitter

Exar Corp has launched two 8bit Sonet/SDH OC-12/3 devices for industry standard optical transceiver solutions.

Exar Corp has launched two 8bit Sonet/SDH OC-12/3 devices for industry standard optical transceiver solutions.

The XRT91L31 and XRT91L32 have best-in-class jitter performance and low power requirements ideal to address cost-reduction trend and increased design margin needs on new and legacy line card designs in add-drop multiplexers, cross-connect equipment and multiservice switches and routers.

"Both transceivers are footprint compatible with competing Sonet/SDH transceiver products enabling ease of device migration for system designers on existing designs while taking advantage of significant performance improvements", said Al Gharakhanian Vice President of Marketing for Networking and Transmission Products Division.

"In contrast to other solutions, Exar's transceivers do not exhibit any crosstalk between the transmit and the receive sections under asynchronous modes of operation enabling superior signal integrity in performance-critical Sonet/SDH applications".

Using the underlying technology footprint from Exar's successful XRT91L30, the XRT91L31 and XRT91L32 are single-chip solutions operating at 622/155Mbit/s Sonet/SDH datarates.

These devices feature very low power dissipation thus eliminating the need for a heatsink or other more elaborate means of temperature management.

The XRT91L31 device features exceptionally low jitter transfer function and exceeds the G.958 Sonet Jitter Transfer Specification by a significant margin in system designs.

The XRT91L31 device can be used in loop timing (repeater) mode for cascading multiple repeaters in transport applications.

The XRT91L32 device features less than 5mUI RMS jitter generation in normal and loop timing modes of operation and greater than 0.6UI jitter tolerance.

"Designers now have access to a range of transceiver choices: OC-3, OC-12 and OC-48 - all from a manufacturer where optical and wireline T/E segments continue to be areas of focus for research and development and future product introductions", said Manmeet Walia, Manager, Strategic Marketing, Sonet/SDH and Advanced Products.

"Exar's PLL technology provides superior jitter performance and a more streamlined solution compared with the traditional use of discrete component implementations as well as other competitive devices".

The XRT91L31 and XRT91L32 can generate all transmit and auxiliary reference clocks from a simple, and low cost crystal oscillator.

The devices support multiple loopback modes that provide complete testability of the system.

The loop-timing mode enables the user to run the transmitter and receiver synchronously.

In addition, these devices are able to detect and generate various alarms and status outputs to provide immediate system alerts and complete fault coverage.

Samples of the XRT91L31 will be available in 30 days.

The XRT91L31 is available in a 64-pin QFP package and requires 3.3V power supply.

The part operates over the industrial temperature range.

In 1000 piece quantities, the XRT91L31 is priced at US $26.40 each.

Samples of the XRT91L32 are available now.

The XRT91L32 is available in a 100-pin QFP package and requires 3.3V power supply.

The part operates over the industrial temperature range.

In 1000 piece quantities, the XRT91L32 is priced at US $24 each.

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