ADC appears inaccurate on old date code parts

[Simon_Buchwald]

We have a design in production using the NRF52833 -QIAAA0, Datecode 224700 and later in the hundreds.

Recently the assembler supplied NRF52833 -QIAAA0, Datecode 2126DS.

The ADC which was calibrated and accurate on DC224700, and now on DC2126DS is significantly different, and measuring lower volts than it should causing the test jig to fail many units.

Nothing in the BOM has changed between runs.

@Nordic - Have there been any hardware changes in the ADC that have not been documented that may affect the ADC even after calibration?

Thanks

Simon

[Kenneth]

Hello,

I am not aware of any changes no, but if there were they should be part of a product change notice:
https://docs.nordicsemi.com/category/nrf52833-category 

I guess the first question is whether you are running the calibration procedure of the ADC every time before sampling?
https://docs.nordicsemi.com/bundle/ps_nrf52833/page/saadc.html#ariaid-title15 

Also, can you share what change you are measuring?

Kenneth