Does nRF52833 Support up to 5.5Volt supply?

[Manish Shukla]

Hi Sir,

We are planning for a Hardware deign by using nRF52833 and we are stuck on what should be suitable the supply voltage. In some case the data sheet showing that it is up to max 5.5voltage and max 3.6 voltage.

In our case we wanted to power up it with a Li-ion battery that will go up to  4.2 volt. So, kindly help us to decide suitable supply voltage for the nRF52833 chip, and does it support up to 5.5 volt supply? if yes , suggest us a suitable reference schematic for the same. 

[Bendik Heiskel]

Hi,

If you want to power the nRF52833 directly from the battery you need to use the internal high voltage regulator, VDDH. Circuit configuration 2 and 4 show how to configure the supply for high voltage mode.

Config 2, is configurting the main regulator in LDO mode, while config 4. Both of these configs is configuring the USB peripheral , but if you don't need it you can connect VBUS directly to GND and have DECUSB floating like in config 6.

The configurations can be combined to get the exact combination you need.

Another option is to use a PMIC in addition to the nRF52833, then the regulator in the PMIC can be used to regulate down the battery voltage and used to supply the VDD net of the nRF52833, bypassing the high voltage regulator. In this configuration VDDH must be connected to VDD like in configurations 3, 5 and 6.

https://docs.nordicsemi.com/category/npm-family

Best regards,

Bendik

[Manish Shukla]

Hi Bendik, thanks for your response on our query. Kindly, also let me know what should be the IO level in VDDH (High Voltage mode). 

[Bendik Heiskel]

The IO level is equal to the VDD voltage level. In high voltage mode the output of REG0 is the VDD voltage and is configurable through the UICR.REGOUT0 register. By default this register is configured to 1.8V.

[Manish Shukla]

Hi,

     Can I connect the 3.3V GPS module's Rx and Tx with MCU pins via 1k in series?

I doubt that during reset the VDD pin will be at 1.8V and it will cause the issue. Please guide.

Also how to write REGOUT0 register?

[Bendik Heiskel]

The register is retained, so once set it will not be reset to 1.8V without erasing the UICR register.

To set the register you can either do this in the application or during program by writing to the register using the programmer.

Here is how we do it for the nRF52840 dongle, which uses  high voltage mode with REG0 configured for 3.0V output:

#include <hal/nrf_power.h>

if ((nrf_power_mainregstatus_get(NRF_POWER) ==
     NRF_POWER_MAINREGSTATUS_HIGH) &&
    ((NRF_UICR->REGOUT0 & UICR_REGOUT0_VOUT_Msk) ==
     (UICR_REGOUT0_VOUT_DEFAULT << UICR_REGOUT0_VOUT_Pos))) {

	NRF_NVMC->CONFIG = NVMC_CONFIG_WEN_Wen << NVMC_CONFIG_WEN_Pos;
	while (NRF_NVMC->READY == NVMC_READY_READY_Busy) {
		;
	}

	NRF_UICR->REGOUT0 =
	    (NRF_UICR->REGOUT0 & ~((uint32_t)UICR_REGOUT0_VOUT_Msk)) |
	    (UICR_REGOUT0_VOUT_3V0 << UICR_REGOUT0_VOUT_Pos);

	NRF_NVMC->CONFIG = NVMC_CONFIG_WEN_Ren << NVMC_CONFIG_WEN_Pos;
	while (NRF_NVMC->READY == NVMC_READY_READY_Busy) {
		;
	}

	/* a reset is required for changes to take effect */
	NVIC_SystemReset();

 

To set it to 3.3V using the programmer you can use this command:

nrfjprog --memwr 0x10001304 --val 5