Power sequence required for nRF5340 Soc

[shahid Sultan]

I have been reviewing the datasheet of the BLE audio nRF5340. It lists multiple power rails in power section.

Is any power-on sequence required for the SOC.

Also, can we use an LDO or buck converter instead of a PMIC IC (nPM1300)?

[Ressa]

Hi Shahid,

Thanks for contacting us. 

No special external power‑on sequence is required for the nRF5340 only thing that is needed is to provide a valid supply voltage within the allowed voltage range.

nRF5340 supports two basic supply modes:

*Normal‑voltage mode: 1.7–3.6 V on VDD (VDDH tied to VDD).
*High‑voltage mode: 2.5–5.5 V on VDDH, internal VREGH then generates 1.8–3.3 V for VDD.
As long as your external supply meet these ranges and you avoid violating brown‑out or USB‑specific constraints, no additional rail‑sequencing is required.

*Regarding using an LDO or buck instead of a PMIC:

You can power nRF5340 from a discrete LDO or buck regulator: the SoC only needs a suitable DC supply on VDD (normal‑voltage mode) or on VDDH (high‑voltage mode). The on‑chip regulators then generate the internal rails.

[shahid Sultan]

If we use the SoC’s integrated power supplies for our application, how much current will they draw? Please provide a power consumption calculation sheet for an audio application.

[shahid Sultan]

The VDD supply voltage can be set to 3.3 V for our application.

[Ressa]

There is no official characterization data about specifically audio applications power efficiency, you can use Nordic PPK kit for that purpose by running your application on SoC to see how is the power efficiency. 

Best regards,
Ressa