Adafruit FRM69HCW Low Power Draw

Discussion Electronics
1

Hi
Has anyone done any testing to see what power the adafruit Radio Feathers / Breakout pull in sleep ?
Testing on the LowPowerLabs site says the RF modules should draw around 0.1micro amps in sleep.

In my testing I get the following which seems high (tested with Power Profiller Kit II)
RFM69HCW 433Mhz Radio Feather - sleep (LowPowerLabs rf69.sleep) - Approx 33 micro amp.
RRFM69HCW 433Mhz Radio Breakout - sleep (LowPowerLabs rf69.sleep) - Approc 90micro amps
RRFM69HCW 433Mhz Radio Breakout - EN pulled Low (3.3V regulator off) - Approx 33 micro amps

Does anyone have any thoughts on why so High ? All I can think of is both modules have 100K pull up resistors on CS and RST. If CS and RST had an input resistance each also of 100K then that would give a quiesant current of 3.3V / (100K) = 33mili amps.

2

So if I measure input resistance with my multimeter from pin to GRND I get around 5Megs, so it doesnt add up ?

3

As a correction. I have been using the Readiohead library and not the Lowpowerlabs library.
In conclusion my testing gives the following results
Adafruit RFM69HCW Featherwing consumes around 33µA in low power mode.
Adafruit RFM69HCW Radio Module consumes around 90µA in low power mode.
Adafruit RFM69HCW Radio Module with Enable pulled low, consumes around 33µA.
Sparkfun RFM69HCW Radio Module consumes 1.33µA in low power mode.

I can only surmise the 33µA is from the 2x 100K pull up resistors used.
The Adafruit RFM69HCW Radio Module has an LDO for 3.3 volts, hence the extra current draw in low power mode.
The Sparkfun module had no pull up resistors!