I need your expertise here. Having a problem with current draw in Standby mode ( STM32F091).
I developed custom board with some external components like Accelerometer, Pressure sensor, temperature sensor, RF comm, EEPROM chip. It is powered from two AAA cels.
I attempted several times to go into STANDBY mode, I have obviously shut down all listed components. After all no success, my board takes around 630uA, it can't go any lower.
this is how I put it in standby:
I wanted to rule out component by component, difficult to do it on final PCB. I had one spare board, so I mounted only power supply part (boost regulator 3.3V). It consumes only 6uA (quiscent current).
Next I mounted STM32F091, and few capacitors mainly ceramic 100nF + 4uF tanatalum, all as advices per ST app note.
Basically I have very clean, isolated setup STM32 + power supply.
At this stage, I doubt there is a hardware issue in the circuit.
I was looking into capacitor leakage, but certainly I did not find anything that adds up to 630 uA of total current.
Did I miss something, can you guys suggest how to approach this problem.