AD9510: datasheet appears to contradict evaluation board schematic which uses balun for single ended ref clock connection.

Document created by analog-archivist Employee on Feb 23, 2016
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There appears to  be a contradiction between the datasheet and the evaluation
board documentation / schematic with regards to the use of a balun for single
ended reference clock connection.

The AD9510 datasheet says: If REFIN is driven single-ended, decouple the unused
side (REFINB) via a suitable capacitor to a quiet ground.

However the AD9150 evaluation board uses a balun to connect to a single ended
reference clock.

Why is that? Is it sufficient to do it without a balun, as it is described in
the datasheet?

 

We use baluns on the evaluation board for the reference inputs because we
typically drive the input with a single ended high end SMA 100 signal
generator. So, the balun allows for more differential swing at the DUT and
higher slew rate too. That’s why we baluns. That said, it’s fine to drive the
reference input single ended and tie off the unused reference input side as
described in the datasheet.

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