[time-nuts] Interesting 1-60 MHz =/- 50 ppb Stratum-3 TCXO chip

[Chris Caudle]

On Fri, May 1, 2020 7:07 pm, mpb45 at clanbaker.org wrote:
> A friend suggested looking into some MEMS TCXO's made by SiTime to
> do this with.  SiTime offers a wide variety of Stratum-3 TCXO chips.
> One of them is the SiT5358 which is spec'd at 0.05 ppm from 1 to 60 MHz.

They also have a small OCXO which is basically one of the TCXO devices in
a small oven:
https://www.sitime.com/products/programmable-ocxos

> I am wondering what any feedback thoughts might be on this from
> the Time-Nuts gang?

They seem to be relatively decent TCXO devices, but they are programmable,
i.e. they use a fractional PLL type technique, so close offset phase noise
is not great compared to a traditional quartz device.
The small size makes the temperature compensation really fast, and the low
mass makes the devices relatively low acceleration sensitive.
SiTime has some graphs showing frequency change when a fan is turned on
and off blowing across the device, and frequency change under various
acceleration conditions.

I am not sure of the cost of the devices.  If you are not cramped for
space and power in your test equipment use case you should see how the
cost compares to a traditional low cost quartz OCXO (or maybe even TCXO if
the accuracy meets your needs in your lab environment, i.e. I don't expect
your lab will vary much more than 10C to 30C even if you were to leave the
house for a couple of weeks).

-- 
Chris Caudle