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STM32L082CZ / Murata Type ABZ CMWX1ZZABZ-078 module - 15 uA in STOP mode; supposed to be < 2 uA

Question asked by Pieter Conradie on Feb 15, 2018
Latest reply on Feb 16, 2018 by T J

Hi everyone,

 

I'm struggling to get the Murata Type ABZ CMWX1ZZABZ-078 module current down to less than 2 uA as stated in the datasheet. At the moment it is about 15 uA. It contains an STM32L082CZ + Semtech SX1276 LoRa transceiver + RF Switch. Any assistance / hints / tips would be greatly appreciated.

 

I created a fresh STM32CubeMX project which puts the SX1276 into Sleep Mode, powers down the TCXO, enables Ultra Low Power mode on the STM32 and puts the STM32 into STOP mode (with the regulator in low power mode). Attached is the whole project for scrutiny.

 

Regarding the STM32, is there anything that I missed that would account for ~ 13 uA in STOP mode?

 

Thanks in advance,

Pieter

 

P.S. I've looked at several examples and tried all the tricks I could find on the internet, but to no avail.

P.S.S. TCXO is powered by PA12, which is supplied by VDD_USB. I have found one source that moved to another pin and did not supply power to VDD_USB. I don't know how this would help and have not tried it.

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