Minimum Decoupling caps

[vkbakken]

Dear support,

What are the absolute minimum decoupling cap sizes running the nrf52810? The application is extremely power sensitive and it is not desirable to have any larger CAPs than strictly required. Bigger the CAP the more leakage - and that is simply not desirable - also the bigger the CAPs the more inrush when turning on. The device runs in LDO mode - as there is no gain from using the DC/DC since sleep vs on cycle is tiny.

Thanks,

-V

[Andreas]

Hi,

 

Unfortunately we are a little reluctant to approving anything but what we have verified internally. Regulators have been dimensioned to the decoupling in the reference schematic, and this is what we verify, diverging from this can cause unpredictable behaviour and worst case an unstable power supply, as I said before.

There is a gradual risk increase as you deviate from the reference schematic though, so you can probably deviate a bit on your own risk if you test and verify well on your end. You mentioned the fact that there is 2x 100nF on the WLCSP part, compared to 3x 100nF on the QFN part - removing the one 100nF on the QFN part should thus probably not cause any issues as long as you do not need it there for filtering.

 

Best regards,

Andreas