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

[Kenneth]

Hi Kiyoshi,

Unfortunately R&D do not have the possibility to do simulation until August. In the meantime I have tried to recreate your problem.

I have tried to recreate your problem here with the attached code with the softdevice enabled, but unable to make it fail yet. Can you modify the code so that it fails or try the project at your side? 

The project can be placed in: \nRF5_SDK_14\examples\multiprotocol

I have received a project from Tak-san, but I have some problems compiling it at the moment, hope to make it compile soon.

Best regards,
Kenneth

 

ble_ant_app_hrm_mod.zip