RAK 4630 Power Rail Design

I’m designing a circuit for a RAK 4630.

From reading other posts, it appears to optimally power the module it is best to supply +3.3VDC and +3.6VDC.

I’m wondering if anyone would know the max power consumption of the rails (full transmit, Bluetooth and LoRa, and processing on the nRF52), so I can pick appropriately sized inductors for max efficiency.

Take a look in the one of base boards documentation: RAK19007



This isn’t what I’m after sadly; I’m well versed in the core setup.

There is no definite value for the max current.
It depends on too many factors, like

  • BLE TX power
  • LoRa TX power
  • LoRaWAN region
  • LoRa packet size
  • LoRaWAN data rate
  • other modules attached to the system
  • and mostly about your application being low power optimized or running useless in the loop() waiting for something to happen

That’s fair. Do you know if it’s an equal split across 3.3v and 3.6v? The 3.3v would be for the SX1262 and the 3.6v is for the nRF?

It depends how you connect the different supply pins.
On the WisBlock RAK4631 it is like shown in the schematics

The SX1262 is supplied by 3.3V and the nRF52 is supplied by 3.6V-4.2V from the battery

I’ll be setting it up like this.

That should be ok. If you have space, I would add some surge protection on the USB+/USB- lines