power connection in normal mode

[Arsen0508]

Hello,

I planned to to use in my design 1.8V. But for redusing power consumption of nrf5340, which way is correct and prefferable: 

1. Use external 1.8V supply in normal mode, when VDD connected to VDDH;

2. connect external voltage to VDDH(3V) and use internal VDDOUT 1.8V(High voltage mode).

one more question...

For program nrf53 should i use voltage level shifter, if my supply is 1.8V

Beforehand thanks,

Arsen

[JONATHAN LL]

Hi Arsen,

For lowest power consumption normal mode is recommended, when it comes to LDO or DC/DC, DC/DC does preform better but it is related to the voltage, better overall performance the higher the voltage.
The LDO might preform equally as good on 1.8V as the DC/DC if there is a minimal difference. Then maybe consider using the LDO. 

Recommended operating conditions.

For program nrf53 should i use voltage level shifter, if my supply is 1.8V

 Do you plan to use a debug\programmer interface or a different DK to program the nrf53?



Regards,
Jonathan

[Arsen0508]

Hi Jhonatan,

Thanks a lot for your suggestion!

I think, we will try to use via SWDIO/SWCLK with other DK. As i understood, in this case, we need level shifter.

Thanks.

Arsen

[JONATHAN LL]

Hi,

It is recommended that you use 4 connections, SWDIO, SWDCLK, GND and VDD. This way you know that the VDD match when you power the target device from the programmer. So if you are able to have 4 pins\connectors that can work as VDD, GND, SWDIO and SWDCLK then that is the simples solution. If you plan to power it externally by battery then you have to make sure the VDD matches, this can be done by a voltage level shifter. 
https://infocenter.nordicsemi.com/topic/ug_nrf5340_dk/UG/dk/hw_debug_out.html?cp=3_0_4_3_9 

Regards,
Jonathan