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Clock chips exceed Sonet jitter specs

Norwood, Mass. — Analog Devices Inc. expanded its clock and data recovery (CDR) offering with four chips that tout outstanding jitter performance to simplify optical network designs.

For designers of datacom and telecom applications, the CDRs simplify system design by exceeding synchronous optical network (Sonet) jitter specifications in all categories (jitter transfer, jitter generation and jitter tolerance) by more than a factor of three, the company said.

The ADN2817 and ADN2818 CDRs for networking applications are said to consume up to 25 percent less power and offer more features than ADI's previous CDR generation.

In addition, ADI is introducing two ultra low-power, fixed-rate ICs that are pin-compatible with its continuous tuning CDRs — and are optimized to minimize the cost and complexity of implementing broadband passive optical network (BPON), according to ADI.

The ADN2817 (650 milliwatts) and ADN2818 (600 mW) are low-power extensions of ADI's family of pin-compatible continuous-tuning CDRs for fixed-rate, multi-rate and continuous-tuning data communications and telecom applications. The ICs are capable of recovering continuous data at rates from 10 megabits per second to 2.7 gigabits per second without external control or the use of a reference clock &#151 making these devices optimal for wave-division multiplexing (WDM) systems that require protocol agnostic capability.

The ADN2817 and ADN2818 offer up to a 1.5-dB improvement in optical sensitivity over ADI's previous generation CDR. Via an I2C interface, optional features such as double data rate (DDR) can be accessed.

The ADN2804 and ADN2806 are fixed-rate CDRs that deliver the low power, features and data rates to exceed BPON requirements. The devices automatically lock to a 612-Mbits/s input data stream without the use of a reference clock or external control. Additionally, in the absence of input data, the devices are able to maintain an accurate output clock. The ADN2804 includes an on-chip limiting amp and dissipates 423 mW, while the ADN2806 has no limiting amp and dissipates only 359 mW.

All four CDRs are packaged in 5 x 5-mm LFCSPs. The ADN2817 and ADN2818 are sampling now with production quantities planned for August 2006, and are respectively priced at $43.74 and $41.55 each in 1,000-piece quantities. Click here for the ADN2817 and ADN2818 data sheets.

The ADN2804 and ADN2806 are available now and are respectively priced at $9.88 and $9.13 each in like quantities. Click here for the ADN2804 data sheet.Click here for the ADN2806 data sheet.

Analog Devices Inc. , 1-800-262-5643, www.analog.com.

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