Need help to select one of available circuit configuration from 6 modes for nRF52840.

[chirag.aumraj]

Hi all,

We develop a custom board using MCU nRF52840(Master) and Module nRF9160(Slave).

1. I confuse to select an available circuit configuration from the reference circuitry schematic of nRF52840(Section 7.3 Product specification nRF52840).
2. Currently, we are generating 3.3V using LDO from the battery to powering up nRF52840 as our device is battery operated.
   1. Output generated from LDO is considered as VDD, Please correct me if I'm wrong.
   2. How to utilize DCDCEN0 and DCDCEN1 in our application?

We do not want to use NFC and Direct USB supply to nRF52840.

Can you please suggest which configuration mode is best suitable with low power consumption MCU nRF52840?

Thanks in an advance for responses.

Best Regards,

Chirag

[Simonr]

Hi

Currently, we are generating 3.3V using LDO from the battery to powering up nRF52840 as our device is battery operated.

 Does this mean that you're using an external LDO? If the battery doesn't generate voltages above 3.6V this shouldn't be necessary, but yes, the output from your LDO should go to VDD_nRF on the reference schematics. 

In our SDK examples, most sdk_config.h files show you how to enable/disable the various DCDC regulators.

For the device you are describing (No NFC or USB supply) I suggest you start out with configuration no. 6 and add the DCDC regulator components from configuration number 4 or 5 (They're the same anyway). The components you need to add are C16 (47nF), L2 (10uH), and L3 (15nH). If something is unclear, please ask.

Best regards,

Simon

[chirag.aumraj]

Hi Simnor,

Thanks for your quick response.

I have a question about power consumption.

If I used DCDC components in configuration no.6 then its power consumption is less or more.

Best Regards,

Chirag 

[Simonr]

Hi Chirag

The DCDC regulator will generally generate a lower current consumption than if you use the internal LDO regulator. You can use the Online Power Profiler to see estimations of various current consumption scenarios, both with and without the DCDC regulator.

Best regards,

Simon