nRF51822 ADC voltage

[wiz_yoo]

Dear sir.

From [nRF51_Series_Reference_manual], ADC maximum input voltage has two rules.

1. The ADC should not be exposed to higher voltage than 2.4 V on an AIN pin after prescaling: Input voltage x prescaling = max. 2.4 V.

2. A GPIO pin must not be exposed to higher voltage than VDD + 0.3 V, according to the Absolute maximum ratings from the nRF51x22 Product Specification.

If ADC input is over maximum input voltage, what happend?

nRF51822 have damage? or reset or do something for protect chip ?

Best and regards. Thank you.

[Stefan Birnir Sverrisson]

Hi

Breaking rule 1 could lead to ADC damage.

Breaking rule 2 mildly will lead to excessive current consumption. Mildly means slightly over VDD+0.3V or for a very short time, i.e. a few milliseconds, with maximum voltage specified in the Abolute Maximum Ratings chapter in the nRF51x22 PS. Breaking rule 2 more than mildly leads to ESD diodes on the GPIO pin to break, which will make the GPIO not function.