SAADC CMR

[Sahar]

Hi,

In the documentaton nERF52832_PS_v1.4, the common mode rejection ratio of the ADC when used in differential inputs is not given in the electrical specifications, where can i found this information?

Thank you in advance

[Jørgen Holmefjord]

Hi,

Unfortunately, we do not have measurements of CMRR for the SAADC. However, based on simulations, it is expected to be better than 50 dB.

Best regards,
Jørgen

[Sahar]

Hi,

Thank you for your reply,

What is the input range of the differential inputs of the ADC ? in the documentation it is indicated that it can not exceed VDD. If the gain is equal to 4 with internal reference, then the input range calculated based on the documentation is equal to 150mV, is it Vp-Vn that can not exceed 150mV or each one of the inputs ? (the differential input or the common mode input)

If we have a differential voltage less than 150mV and a common mode voltage of 2.5V, can we use the ADC in this configuration (internal reference with gain 4) ?

Thank you in advance

Sahar