time-nuts@lists.febo.com

Discussion of precise time and frequency measurement

View all threads

Oscilloquartz 8663 warm up behavior

PB
Peter Bell
Thu, Sep 29, 2022 1:54 AM

Hi,

I was just testing one of these oscillators, and the current
consumption seemed rather strange - according to the datasheet, it should
take a maximum of about 8W during startup (I.E. about 650mA), but what's
actually happening when it's powered up from cold is that the initial
current is of the order of about 230mA - as it warms up (as observed by the
output frequency coming close to nominal), the current will suddenly jump
to about 550mA then start to slowly drop, finally settling at about 150mA.

I can see reasons this might happen (for example, if the outer oven is
disabled until the inner oven gets close to the operating point), but have
no idea if this is something you would expect to see with these units or
not.

So I just wondered if someone on the list has experience of these units and
can say if this an indication of some sort of fault or expected?

Regards,

Pete

Hi, I was just testing one of these oscillators, and the current consumption seemed rather strange - according to the datasheet, it should take a maximum of about 8W during startup (I.E. about 650mA), but what's actually happening when it's powered up from cold is that the initial current is of the order of about 230mA - as it warms up (as observed by the output frequency coming close to nominal), the current will suddenly jump to about 550mA then start to slowly drop, finally settling at about 150mA. I can see reasons this might happen (for example, if the outer oven is disabled until the inner oven gets close to the operating point), but have no idea if this is something you would expect to see with these units or not. So I just wondered if someone on the list has experience of these units and can say if this an indication of some sort of fault or expected? Regards, Pete