https://devzone.nordicsemi.com/f/nordic-q-a/26213/nrf51822-sleep-mode-with-high-frequency-clockI am using NRF51822,S110,16Mhz XOsc. In this if Controller goes to sleep mode the current consumption is 4.9mA. In my application at sleep mode BLE should be connected and ADC runs at timer interval.Is it possible to reduce power consumption less thanen-USTelligent Community 13Tue, 24 Oct 2017 09:16:51 GMThttps://devzone.nordicsemi.com/thread/103236?ContentTypeID=1Tue, 24 Oct 2017 09:16:51 GMT137ad170-7792-4731-bb38-c0d22fbe4515:2232811c-c6ad-400f-bde6-0c8157eca26dBj&#248;rn Kvaale<p>If I were you, I would use an external crystal as a low frequency clock. That way, you sacrifice a bit of timing resolution, but get much better power consumption (e.g. instead of 5-70 uA using the HFCLK, you use about 0.1 uA). You could also use the <a href="https://devzone.nordicsemi.com/question/953/what-low-frequency-clock-sources-can-i-use/">internal RC oscillator</a> if you don&#39;t want to use the external crystal, although this would increase the current consumption to around 8-10 uA. This is because the RC oscillator must be calibrated every 4 seconds using the HFCLK. <a href="https://devzone.nordicsemi.com/question/33972/use-external-32mhz-crystal/">Here is a guide</a> to setting up the external crystal if you decide to go with that.</p><div style="clear:both;"></div>