LPM3 current and ACLK Source

I am trying to achieve low current  in LPM3 on a MSP430F5419a. I am running a small test app that  enables 2 GPIO interrupts and the RTC Alarm interrupt then sets the GPIO pins for low power and enters LPM3 (with interrups enabled).  The app flashes and LED several times when it wakes up to verify that the interrupts are working. With XT1 running on a 32k crystal and ACLK source XT1 the current in LPM3 is 6-7uA. If I don't enable the crystal and set ACLK source to VLO the LPM3 current is 2uA. With no crystal and ACLK source as REFO the LPM3 current is 5-6uA. We were expecting to - and are hoping to -  acheive something like 2uA in LPM3 with the RTC running in crystal mode.

1 Reply

  • Dwight,

    How are you measuring the quiescent current?  Is this the current to the processor to your board?  While the datasheet certainly indicates that ~2uA is possible at 25 degC running from XT1 (pg 42 of SLAS655C) it does indicate this current is dependent on the supply voltage and temperature.