Powering & Circuit Configurations for the NRF52840

[ryerye120]

I'm kind of confused about the DCDCEN0/1 related functionality and can use some confirmation. If I'm hoping to run everything at 1.8V, it seems I can wire VDD_NRF to 1.8V and then expect all my GPIO to operate with a VDD_high of 1.8V. Is that correct? Does that mean I can just ignore high voltage mode and the DCDCEN0/1 blocks?

In terms of wiring the nrf52840 on my PCB, does that mean I could use config 3 from the datasheet (screenshot below)? From my understanding, this should work fine on startup and not limit my SPI read/write rate or my BLE functionality.

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fps_nrf52840%2Fref_circuitry.html&cp=4_0_0_6_2

Big thank you to anyone who can help!

Kindest regards,

Ryan

[Jared]

Hi,

If you want to power the nRF52840 with 1V8 then Normal voltage mode is the correct one to use. Shorting VDD and VDDH together will configure the nRF into Normal mode which means that it will omit the first regulator stage REG0. The schematic that you shared is indeed Normal voltage mode as VDD and VDDH is shorted, in addition it doesn't use the external DCDC regulator but instead the internal LDO as the DCDC external components is not included. This will work fine.

regards

Jared