Hello, We're currently developing PCB with nRF5340_CLAA SoC. For specific reasons, main supply voltage was changed from stable 3.3V to 3.5V that comes from DC/DC converter. Voltage in some scenarios can goes up to 3.7-3.8V for few miliseconds when Converter is in startup phase. As previously we consider to set nRF53 in normal voltage mode (DC/DC), now It looks like we have to change operation mode to high-voltage DC/DC mode. Therefore, I have a few questions that I cannot find or understand in the technical documentation. When nRF53 is set to HV mode, VDDH pin is the only one Voltage Input Pin? What is the current efficiency of this input? We will not use VBUS pin as device will not have USB functionality and external Power Supply will be managed from external components. When nRF53 is set to HV mode, do VDD inputs become voltage outputs or needs to be connected to main supply voltage together with VDDH? What is the maximum constant current of internal VREGH regulator available to supply external devices? Best Regards, Lukasz

nRF5340_CLAA High Voltage Mode Electrical Limitations

Hello,

We're currently developing PCB with nRF5340_CLAA SoC. For specific reasons, main supply voltage was changed from stable 3.3V to 3.5V that comes from DC/DC converter.
Voltage in some scenarios can goes up to 3.7-3.8V for few miliseconds when Converter is in startup phase. As previously we consider to set nRF53 in normal voltage mode (DC/DC), now It looks like we have to change operation mode to high-voltage DC/DC mode.

Therefore, I have a few questions that I cannot find or understand in the technical documentation.

When nRF53 is set to HV mode, VDDH pin is the only one Voltage Input Pin? What is the current efficiency of this input?
- We will not use VBUS pin as device will not have USB functionality and external Power Supply will be managed from external components.
When nRF53 is set to HV mode, do VDD inputs become voltage outputs or needs to be connected to main supply voltage together with VDDH?
What is the maximum constant current of internal VREGH regulator available to supply external devices?

Best Regards,

Lukasz

0 JONATHAN LL over 3 years ago

Hi,

This will depend on the spikes duriation and size, at 3.8V it should be fine to stick to normal voltage mode, only using VDD, as stated in the PS for max rating https://infocenter.nordicsemi.com/topic/ps_nrf5340/chapters/abs_max_ratings/doc/abs_max_ratings.html?cp=3_0_0_10 3.9V is max value.

The efficiency will depend on the voltage, not just if it is in normal or high voltage mode.

When the nRF53 is in High voltage mode then VDD will "output" voltage, as indicated in the infographic here: https://infocenter.nordicsemi.com/topic/ps_nrf5340/chapters/supply/doc/power_supply.html?cp=3_0_0_3_4_1#high_supply_mode .

Most of the info you are seeking is here: https://infocenter.nordicsemi.com/topic/ps_nrf5340/chapters/supply/doc/power_supply.html?cp=3_0_0_3_4

Max constant current is listed here: https://infocenter.nordicsemi.com/topic/ps_nrf5340/regulators.html?cp=3_0_0_3_6_4#unique_1521528095

Regards,
Jonathan
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