Power rail requirements on SoC during sleep/HIDOFF?

[Anonymous]

Is it possible to power down any of the power rails, ie VDDC/VDDO when the device enters deep sleep or HIDOFF?  If so can the firmware trigger a GPIO to enable/disable an external regulator when switching power modes?  Furthermore, if the design was an SoC where the radio will never be used (consider it a de-featured product where we wish to leverage existing firmware effort), can any of the other RF-related power rails such as VDDIF/VDDFE/VDDVCO/VDDPLL be permanently grounded?

rob.mitrunen

[Anonymous]

Hello Andrew,

Is it possible to power down any of the power rails, ie VDDC/VDDO when the device enters deep sleep or HIDOFF?

[JT] VDDO needs to be enabled to power up a GPIO

If so can the firmware trigger a GPIO to enable/disable an external regulator when switching power modes?

[JT] - The Internal LDO can actually disable the core and radio to ~0V, but again, you still need 1.8V for GPIO.

Furthermore, if the design was an SoC where the radio will never be used (consider it a de-featured product where we wish to leverage existing firmware effort), can any of the other RF-related power rails such as VDDIF/VDDFE/VDDVCO/VDDPLL be permanently grounded?

[JT] The core can be set to ~0V, but you still need to wake up using 1.8V GPIO - This rail also powers up the EEPROM or Serial FLASH where your code is stored.

Hope this helps,

JT mwf_mmfae

[Anonymous]

Hi JT,

I figured as much w/ VDDO but it's still not clear if we can use a firmware-controlled GPIO to enable/disable an external regulator that powers VDDC?  Or do you suggest possibly using the ~1.2V output of the LDO itself to do this?  Or is it best to just stick w/ using the internal LDO to power VDDC despite the higher active source current?

Also, what about all the RF rails (VDD_RF domain in the datasheet)?  Must they be powered even if the radio will never be used?  The above wasn't clear.

Thank you,

Andrew

[MichaelF_56]

Note that you can not turn the radio off.

However, if the application turns off all adv, scans and connections, the RF HW block will not transmit/receive anything.

[Anonymous · Accepted solution]

Hello Andrew,

You need 1.8V on the GPIO in order to wake up from a GPIO

The GPIO 1.8V needs to be present before the 1.2V Core and Radio.

Thanks

JT