On 4/13/17 6:17 AM, Bob kb8tq wrote:
Hi
It’s a good bet that there is at least one regulator IC inside any modern OCXO.
As you slowly ramp the input voltage on a regulator, various odd things may
or may not happen. A 1 mv / s ramp on the outside can be “who knows what”
at the oscillator level. That said, slow voltage ramps are a really good way to
put
all sorts of oscillator circuits into really odd modes. Clock oscillators
(XO’s) and MCU
built in clock circuits very definitely fall into this category.
The same sort of “who knows what” problem also gets into the rest of the
circuit.
A limited supply might work fine nine times out of ten or 99 out of 100. On the
odd time out, something goes poof !
Bob
This is a known problem with many FPGAs, particularly those which
configure themselves from on or off-board flash memory.
They have all sorts of little sequencers internally which are driven by
(very non-time-nuts-quality) oscillators.
And even some non-flash based anti-fuse parts:
https://www.microsemi.com/document-portal/doc_view/130010-ac344-board-level-considerations-for-power-up-and-power-down-of-rtax-s-sl-fpgas
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
