RAK3172-F electrical specifications: 3.0 V operation, ADC reference and power consumption

LPWAN Modules / EVBs RAK3172
1

Hello all,

I’m evaluating the RAK3172-F for a battery-powered application using a fixed 3.0 V or 3.3 V supply.

I found the F-specific supply range in the linked documentation, but would appreciate clarification on the following points. Please specify the applicable hardware revision and RUI3 version.

  1. Operating voltage

Does the specified 2.3–3.6 V range cover all module functions, including startup, radio operation and external-flash programming/erasing?

Is continuous 3.0 V operation supported across the module’s rated temperature range? Are there additional voltage requirements for firmware updates or flash writes?

  1. ADC reference and voltage measurement

Is the RAK3172-F ADC reference internally connected to VDD, or can another reference be selected?

If it follows VDD:

  • Does analogRead() return raw ADC counts without assuming a 3.3 V reference?
  • Is there a supported RUI3 method to read VREFINT and its factory calibration value to compensate for actual supply voltage?
  • Does api.system.bat.get() assume a specific board, divider ratio or supply voltage?

Please provide the supported ADC pins, input-voltage limits, recommended source impedance and available sampling-time settings. A minimal F-specific voltage-measurement example would help.

  1. RF output and current consumption

For the US915 variant, are measured TX-current and conducted-output-power figures available at 3.0 V and 3.3 V, particularly for +20 and +22 dBm settings?

What happens if +22 dBm is requested at 3.0 V? Is the setting limited, or does actual RF output differ from the requested value?

Please also clarify RX and MCU-active current, including the measurement conditions and whether figures include the complete module.

  1. Sleep current and GPIO states

What firmware settings and peripheral states are required to achieve the specified sleep current? Does that figure include the external flash and TCXO?

Are sleep-current measurements available at 3.0 V and across temperature? Can GPIO outputs retain their states during sleep, and what states should be expected during reset and bootloader operation?

  1. Startup and brownout behavior

What supply-ramp, decoupling and startup peak-current requirements should a custom PCB follow?

What are the recommended brownout settings, particularly to prevent corruption during flash writes or interrupted firmware updates?

  1. Max current and voltage requirement while FUOTA

Thanks
Subhadeep