Errata 202 and decoupling capacitors

[ataii]

We are designing a circuit that will be supplied from lipo battery, vddh.  I am wondering how decoupling capacitors on vdd will impact as it is suggested (in errata 202) to not draw power for 1ms after start. Can it be that decoupling capacitors draw current until they charge and cause the chip to not start? Thanks..

[bjorn-spockeli]

Hi Ata, 

are you referring to decoupling caps for external circuity powered from VDD(i.e. REG0 output) or the decoupling caps that are a part of the nRF52840 reference circuitry? If it is the latter 

Errata 202 takes the current draw of these decoupling caps into account, hence the when the workaround states

Do not draw current from VDD pin (external circuitry supply) during power up and ensure VDDH rise time to 3 V is below 1 ms.

it only applies for external circuits powered from the nRF52840's VDD.

Bjørn 

 

[ataii]

Yes, i was referring to reference circuit. I turn on the external components via a mosfet. Then i assume it will work as intended. Thanks a lot!