Hello,
I have a customer using the MSP430F6638 and when applying the battery (or power supply) to the system they are sometimes seeing ~3mA of quiescent current. When they leave the battery disconnected for a longer period of time (longer than a few minutes) the system will pull ~3mA when it turns on. If the the disconnected for a short period of time (10 second), the system will only pull 10s of uA when it turns on. The 10s of uA is the expected system draw. During these boot ups we are keeping the MSP430F6638 held in reset.
We have narrowed down the current draw to the MSP430F6638 device. We confirmed that a brown out on reset is not a root cause, see DVCC scope shot below. White line is when the system boots up at 10uA, the blue line is when the system boots up at 3mA.
They have DVCC and AVCC powered by the same 3.3V boost converter off of 2x AAA batteries. But they also have VBAT (pin 87) connected to the batteries directly. We are unsure if there could be higher current draw if VBAT comes up before DVCC/AVCC.
The rise time of DVCC/AVCC is ~500us, would that cause any issue? (the scope shot above used a current limiting resistor which extended out the rise time, normal rise times are 500us)
Thanks,
Nick
