Why is the AD9467-FMC-250EBZ missing the on-board oscillator Y200?

Document created by UmeshJ Employee on Jan 12, 2015Last modified by UmeshJ Employee on Jan 26, 2015
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Questions have been raised regarding the AD9467-FMC-250EBZ on-board oscillator.

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At the time of the design of the board, the only available crystal oscillator that was cost effective, yet gave ok performance for the AD9467 was the one designated Y200 on the board. The performance (SNR) was not adequate. The only reason this was included was to enable some sort of evaluation, even though the crystal oscillator gave inferior performance. The Y200 was disabled by default because of the inferior performance. This was a double edged sword as now customers evaluating the AD9467-FMC-250EBZ wanted to see datasheet performance with the on-board oscillator. The Y200 was never meant to be the default clocking solution, but when it was enabled, customers expected datasheet performance. There were questions from the field as to why the oscillator was provided as an option when the performance was bad.

 

In the meantime, ADI has been able to evaluate another 250MHz crystal oscillator, the CCSO-914X series. This series of SAW oscillators gave good SNR/SFDR performance for the AD9467-FMC-250EBZ. The SNR/SFDR performance across input frequency is shown below:

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As can be seen, the CCSO-914X offers much better performance that the previous on-board oscillator. The AD9467-FMC-250EBZ boards are being modified to incorporate the CCSO-914X. In the meantime customers can contact Crystek Microwave regarding the availability of these crystal oscillators in their "RED BOX" variant.

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