RE: nRF5340 Hardware Design Questions - VDD, VDDH, VBUS

JONATHAN LL — Tue, 12 Mar 2024 13:16:01 GMT

Hi Sean,

[quote user=""]Is the VDD regulator capable of powering the nRF21540? [/quote]

No.

[quote user=""]If I need to instead add an additional 3.3V external regulator to power the nRF21540, is it better to power the nRF5340 from the same external regulator, or just keep it connected to VBUS?[/quote]

It depends on your use case, so there is no real correct answer here. But using a single regulator to supply both the nRF5340 and the nRF21540 will be less complex and likely cheaper then having two regulators on board.

We do also provide PMIC's so you could look in to that if you want. https://infocenter.nordicsemi.com/topic/struct_pmic/struct/pmic.html?cp=7

[quote user=""]Are the decoupling capacitors on the VDD line required when the VDD is in output mode?[/quote]

Yes they are still required.

[quote user=""]Are decoupling capacitors required on the VDD pins where nothing is connected?[/quote]

all (relevant)components shown in the ref. circuit should be added.

[quote user=""]As VDD is in output mode, is it still required to tie all of the VDD pins together?[/quote]

yes.

You can see more info on how the regulators work in these sections:
https://infocenter.nordicsemi.com/topic/ps_nrf5340/regulators.html?cp=4_0_0_3_6
https://infocenter.nordicsemi.com/topic/ps_nrf5340/chapters/usbregulator/doc/usbregulator.html?cp=4_0_0_3_7

Regards,
Jonathan