[time-nuts] Si5351B

[D. Jeff Dionne]

On Feb 4, 2019, at 14:25, Achim Gratz <Stromeko at nexgo.de> wrote:

> The Si5351 needs something between 25MHz and 27MHz as reference.  

That isn't true.  Even the B version works just fine with a OCXO input directly.  See my thread here:
https://www.silabs.com/community/timing/forum.topic.html/si5351_msop10_packag-wocK <https://www.silabs.com/community/timing/forum.topic.html/si5351_msop10_packag-wocK>

The problem is the Silicon Labs software to calculate the registers flags an error, so you have to calculate them yourself.  This is not hard, there are programs and references on the web.

> I'm currently mulling if it's worth the risk going slightly lower, as there are nice and cheap OCXO at 24.576MHz I could actually buy, whereas my options at the actual range boil down to just a single unit (I've only looked at two distributors, though).

That will certainly derisk the design, but it will not solve the SiLabs software issue.  Having used this approach, I can say my sampling of Si5351 chips with 10MHz OCXO all worked just fine, so 24.576MHz certainly will.

J.