What is the crystal accuracy ppm on the XEM3001 boards?
The markings on the can I’m looking at is 2400ECSXR I’m having trouble getting that back to a part spec.
Sorry if I’m missing this in the docs but I can’t see it yet.
thanks
Stephen
It is around 50ppm, but it is not spec’ed or guaranteed.
Thanks for that, all I needed to know.
Hi,
For Crystal accuracy you have to consider : initial tolerance (manufacturing) and temperature coefficient.
Indeed, crystal frequency varies with its temperature : typically about 1 ppm / degree C for AT cut crystal, but slope varies
In general, crystal temperature is ambiant temperature + a constant delta (ie 10?C)
Check this excellent TN :
http://literature.agilent.com/litweb/pdf/5965-7662E.pdf
Furthermore, as XEM boards provides 2 sources for clocks (ti_clk = clk reconstructed from USB and other clocks made from board quartz + PLL) i think accuracy could be assessed (at least vs host PC USB clk which maybe of a better accuracy)
Another idea : write a little C application using NTP (or even better : a GPS device ) => you can then assess XEM quartz drift in various ambiant temperature
Regards