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Not expected rising current in Sleep mode

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adhoc_user:
Hi folks,

we are testing our stm32L4 with a LoRaModule (SX1278 named as RA-02).
We always (tested with 2 boards) have a unexpected rising curve of the current after a TX-transmission or touch event.
If we push the RA-02 module to a side with little force or touches some pads of the module the current is falling to the real sleeping current(µC is sleeping).
But a few seconds later the current is rising again :scared:. And the module is well soldered, we have checked every solder joint.

If we disconnect the vdd jumper brigde (only for this module) the current has a permanent low value. So the circuit after this vdd bridge to lora should be the problem.

What caused the rising current? Bad PCB? Bad Connections?
Thanks in advance for hints!

adhoc_user:
OK, solved by myself.

The lora-module has in sleep mode an active SPI_CS pin, you can wake up the module with spi.
By default our µC-pins are in analog mode with high impedance in sleep mode.
This pin on sx1278 needs a permanent pull-up in sleeping time. Otherwise its floating and does "something" which cause the extra current.

Now we have ~60µA  :popcorn:

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