oscillation at the embed analog front end circuits of SAADC in nRF52832

[Kiyoshi Iwai]

Hello,

I found the strange phenomena on nRF52832.

By using the SAADC, I have some noise on ADC Data only at a certain temperature range.

Temperature range is depend on individual IC.

I might be the circuit oscillation at analog front end of SAADC, I think.

(internal reference voltage or op amp etc,)

I tried to switch DCDC on/off, but there's no difference on phenomena.

Anyone can resolve it?

I attach the files of real data and measurement condition.

Best regards,

Kiyoshi Iwai

3426.SAADC_noise_devzone.zip

[Kiyoshi Iwai]

Hello Kenneth,

Thanks for reply.

I checked it again by using your instruction, but  nothing changed.

The clock doesn't concern this phenomena, I think.

What do you think about it?

By the way,  HFCLK staus are the following, what clock will be used at ADC?

SRC=1 (HFXO),  STATE=0 (not running)

best regards,

Kiyoshi Iwai