Recently we noticed a strong power consumption increase in a new revision of an existing product based on the MSP430F5257. The product normally uses around 15uA in sleep mode, the new revision product uses around 150uA.
We traced this back to a change in the components connected to the P5.5/XOUT pin. This pin is configured (in sleep mode) as input GPIO with in the new revision an external pullup to 1.8V which the old version does not have. When experimenting with the pull up voltage we noticed: 0.8V to 1.65V additional power consumption: 0 to 120uA and 1.65V to 2.5V additional power consumption 120uA to 0.
In our opinion all related registers are configured correctly.
Details
XT1 is OFF. P5.4/XIN not connected and set as GPIO output tot '0'. P5.5/XOUT as GPIO input, no internal pull up/down configured.
DVCC: 3.3V
DVIO: 1.8V
What can be causing this increased power consumption?
Is this expected behaviour?