Regarding nrf52840

[Alan Ajit]

Dear nordic,

I have some doubts in nrf52840. 

1. How this VDD_nrf voltage generate?

2. Is this VDD_nrf voltage only depend on Hardware or is itany dependency in software?

3. For proper working of chip is it any register need to write?(for example UICR register)

can you clarify my doubts. I have a custom board this get VDD_voltage 1.8v always .

[Andreas]

Hi,

 

See the POWER - Main supply section of the PS. When feeding the SoC through VDDH, there is a 'high votlage' regulator stage that steps down the voltage on the 'VDD' rail, the voltage of which you specify in UICR.REGOUT0. If you do not specify anything here, VDD will be 1.8V by default.

 

Best regards,

Andreas

[Alan Ajit]

Thanks for your replay. my doubt is not cleared. in my circuit VDDH is 3.7v and VDD is connected to VDD_nrf. I think its in high voltage mode is it right?

1. its not clear what is the difference between this modes. for better power consumption which mode is better?

[Andreas]

Hi,

 

If VDDH and VDD are not connected together externally, the device will be in high voltage mode. We have little specifications on power consumption differences other than what is in the PS, but at 3.7V you will exceed the supported supply range for normal mode.

 

Best regards,

Andreas