topic Re: VREF chop oscillator? in Kinetis Microcontrollers

VREF chop oscillator?

scottm — Fri, 24 Nov 2017 17:54:14 GMT

The K02 reference manual mentions a chop oscillator but doesn't explain what it is. A quick Google search doesn't return anything obviously relevant. I'm not an analog guy and I could only name a handful of oscillator types, and I'm not clear what the oscillator is doing in the VREF module.

I'm seeing some weird behavior from VREF and I'd like to better understand how it works. Is there any documentation on this subject?

Thanks,

Scott

Re: VREF chop oscillator?

Hui_Ma — Mon, 27 Nov 2017 08:08:29 GMT

Hi Scott,

Unfortunately, there is no more info about VREF module chop oscillator.

What's the weird behavior you mentioned? Thanks.

Have a great day,
Mike

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Re: VREF chop oscillator?

scottm — Mon, 27 Nov 2017 16:24:34 GMT

Hi Mike,

The main problem turned out to be a missing decoupling capacitor. It'd still be nice to know exactly what the chop oscillator is and what it does, but it doesn't seem to affect the power consumption noticeably so I'll leave that part alone for now.

Thanks,

Scott

Re: VREF chop oscillator?

scottm — Mon, 27 Nov 2017 17:22:23 GMT

Unfortunately, there is no more info about VREF module chop oscillator.

For future reference, what's the recommended procedure for dealing with this? We've established that there's no more information about the feature in the published documentation. I've posted to the official support forum and been told that there is no more information. Will I get that same response if I submit the question as a support request? Or is the VREF chop oscillator now in the same category as Stonehenge - lost knowledge of the ancients that we can only attempt to infer from the clues they left behind?

Scott