nRF52840 DC DC regulator hardware connection

[SandeepG]

Hi All,

I am using nRF52840 chip in one of my battery powered design. As I could see the datasheet and power calculator says the current consumption of nRF is less in DC DC regulator mode than in LDO mode. I would like to know what are the changes to be done in schematic to incorporate the DC DC regulator mode. As of now I am following the configuration 6 of nRF datasheet(which is in default LDO mode), please refer to page 595 of datasheet.

The design is not having USB, hence the VBUS is tied to GND. I have designed for normal voltage mode, hence VDDH and VDD is shorted. DCCH and DECUSB is left open. So now to enable the DC DC regulator mode in Hardware, if I connect two inductors in this way. DCC --> 10uH --> 15nH --> DEC4 and DEC6. Is this hardware connections fine and enough to make nRF to work in DC DC regulator mode or any other changes required? Please let me know. Awaiting early response. Thanks in advance.

Regards,

Sandeep G

[Andreas]

Hi,

 

See the POWER chapter in the PS. Enabling the DCDC mode requires the external 10µh+15nH between DCC and DEC4 for DCDC1 (normal voltage), and an external 10µH between DCCH and VDD for DCDC0 (high-voltage), so your description sounds correct. Remember that you still need to enable the DCDC mode in your FW, just populating the components on the PCB will not turn it on automatically. Feel free to submit your design in a private case for a free design review.

 

Best regards,

Andreas