nRF52811 ADC resolution and enob

[JsSenso]

Hi,

I am developing a custom board with nRF52811 where I will measure analog signals from op amp on ADC (single ended mode). Signals will be very small, so I need a good resolution. nF52811 and the board will operate on 1.9V supply, so I will need 12-bit resolution on ADC. This was actually the main reason for choosing nRF52 chip in the first place.

According to datasheet (SAADC Electrical Specification, page 281-282) the effective resolution (ENOB) is only 9bits, which is to low for me. There was already a similar topic on DevZone nRF52 ADC ENOB, but I still need some more clarifications regarding this topic.

• According to datasheet 9-bits ENOB is for differential mode with 1/1 gain. What will be the ENOB for single ended mode and gain 1/3?
• It was mentioned that the best ENOB for 12-bit can be 10.5bits (with oversampling), which is not much better for me compared with 10bit. What is ENOB for 10-bits (this parameter is missing in datasheet)?
• What is VOS for 12-bits (this parameter is also missing in datasheet)?

Thanks for any help, Jure

[JsSenso]

Hi,

can someone from the Nordic Tech Support team please provide the missing data noted above.

And also, I really need an information if it is possible to achieve 12-bit (effective) resolution on nRF52811 adc.

Thanks, Jure

[Jørgen Holmefjord]

I'm checking with the designers. Will get back to you as soon as I receive their response.