RE: ADC current consumption

Turbo J — Thu, 22 Mar 2018 09:36:19 GMT

Don't forget the clock. ADC needs HFCLK or HFINT running, which consumes additional current if it was not active otherwise.

RE: ADC current consumption

GT Software — Thu, 22 Mar 2018 09:21:36 GMT

I don't have an nRF51822 to hand (I assume you mean that chip) but I found these pages

https://devzone.nordicsemi.com/f/nordic-q-a/13907/adc-consumption which gives a mA value for a particular scenario.

https://devzone.nordicsemi.com/b/blog/posts/measuring-lithium-battery-voltage-with-nrf51 which gives a nicely detailed approach to reading the battery voltage.

From a theoretical point of view, the nRF51822 Product Specifcation v3.3 ( http://infocenter.nordicsemi.com/pdf/nRF51822_PS_v3.3.pdf ) section ' 8.12 Analog to Digital Converter (ADC) specifications' shows an 8-bit ADC sample takes 20 us, 10-bit ADC sample takes 68 us and the ADC power is 260 uA so combining those with your voltage will give a rough power consumption just for the ADC (ignoring having the core waking up etc.)