Hi,
I have my own STM32 development board that I am interfacing to an Xbee 3. I have chosen to delay switching the Xbee3s power supply on until I need to use the transceiver.
However, when I do switch the Xbee3 on I an getting significant voltage drop on the 3.3V supply and I’m getting a negative voltage spike on the Xbee Vin line.
The image shows the 3.3V volt supply in purple and the Xbee Vin line in yellow.
Yellow starts at 0V.
Time base is 1uS per div
The spike I get on the 3.3V line is causing my processor to brown out.
I am using an LDL1117S33R which is good for 1.2A.
The only details I can find about inrush current considerations is for the Digi XBee® 3 Cat 1 Smart Modem which has an inrush of 2A.
Is switching these devices possible and/or not recommended?
I would suggest adding additional capacitance on your VCC line after the voltage regulator. You may want to talk to the power supply manufacture for suggestions. I would also suggest looking at the interface board schematic located at https://hub.digi.com/support/products/digi-xbee/digi-xbee3/