DCCH voltage level with DCDCEN enabled during deep sleep on nRF52840?

[Kaihi]

Hi, I'm working on a project and I need the GPIOs to have 3.3V available when the nRF52840 is in deep sleep, in order to use wake-up on GPIO. So I'd like to know what the DCCH voltage is when DCDCEN is enabled and the device is in deep sleep.

Does the DCDC completely turn off in deep sleep, and does the internal LDO take over?
If so, does the internal LDO regulate down to 1.8V or 3.3V?

The idea is to power VDDH with a LiPo battery.

Also, I read on this forum that the quiescent current of the DCDC on DCCH in idle is around 35 µA — how much would it be in deep sleep?

Thanks in advance!

[snoopy20]

In deep sleep the DCDC is definitely turned off because most peripherals are off. The DCDC only turns on when certain ones are used, mainly BLE.

I'm unsure what you exactly means by DCCH. The pins are using MOSFET's to Vdd either direct or through a weak-pullup equivalent so if your Vdd is 3.3v or 3.6v that's what they'll see. The 1.8v is purely internal, you can't access it.

[Kaihi]

Hello snoopy20 thanks for your response, with DCCH I mean it is the pin that VDDH uses for the DCDC converter right?

But for example the battery is 4.2v when fully charged, connected to VDDH only and not VDD, it will be 4.2v the voltage for the GPIO when the nordic is on deep sleep?

When nordic is on I will use the internal dcdc converter at 3.3v.

[Vidar Berg]

Hello,

The IO voltage is the same in System OFF mode (deep sleep) as in active mode and is controlled by the REG0 regulator stage (GPIO levels).