https://devzone.nordicsemi.com/f/nordic-q-a/14365/nrf52-adc-front-end-circuitHi, I&#39;m developing a nRF52 application that exploits two ADC channels in single ended configuration. VDD is 3.0V. For the signal conditioning I&#39;ve chosen a driving Op Amp OPA342 followed by a RC Low Pass filter. The RC filter limits the out-of-banden-USTelligent Community 13Thu, 09 Jun 2016 17:07:46 GMThttps://devzone.nordicsemi.com/thread/54854?ContentTypeID=1Thu, 09 Jun 2016 17:07:46 GMT137ad170-7792-4731-bb38-c0d22fbe4515:25c28953-e089-4e58-bd4f-055acf1f2888Carsten Wulff<p>The input of the SAADC should not be that hard to drive. The input cap is a switched capacitance of up to 2.5pF (see PS for details), and even at 100kOhm source resistance it has a time constant of 0.25us, so even with 12-bit settling, which requires -ln(1/4096) &gt; 8.32 time constants to settle, the kick back will settle in a few micro seconds.</p> <p>It&#39;s generally when a SAR runs at ten&#39;s of mega hertz and up you need to worry about the kick back.</p> <p>I&#39;ve tested the SNDR with a 50 Ohm to ground on the PCB to match the signal source impedance, a AC coupling capacitor close to the chip, with a 10pF decoupling on the SAADC input, and setup the common mode at the input with the RESN and RESP dividers.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/54853?ContentTypeID=1Wed, 08 Jun 2016 15:05:25 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f596b364-c9a2-4140-9557-2de4d8da9a0aAnders Strand<p>You might find some useful info in <a href="https://devzone.nordicsemi.com/blogs/943/measuring-lithium-battery-voltage-with-nrf52/">this</a> blogpost.</p><div style="clear:both;"></div>