LPW3 power: different between 1.8 and 3.6V supply?

Matt Shira said:

In operating mode, does MSP430F2274’s power consumption depend on power supply voltage?

Yes.

Matt Shira said:

In LPW3 mode, does MSP430 power consumption depend on its power supply voltage?

Yes.  Total power consumption generally has 2 components, static and dynamic.  When in Low Power Mode 3, the static power consumption due to quiescent current draw would be the dominant factor.

Ptotal = Pstatic + Pdyn
Pstatic = Istatic * V
Pdyn = Idyn * V

Matt Shira said:

And do the answers above also apply to G series devices?

Yes.

BrandonAzbell said:

Ptotal = Pstatic + Pdyn
Pstatic = Istatic * V
Pdyn = Idyn * V

Well, I might add that Istatic isn't static. While the change is less significant as on a pure resistive system, the leakage current still somewhat depends on supply voltage.

On a resistive system Pstatic = Istatic * V = V * V / R.
On semiconductors, the term I=V/R isn't true anymore. Because R is something non-linear depending on meterial, temperature, even the current itself, sorrounding ME fields etc.

However, the smaller V is, the smaller the leakage currents are - just that it is a highly non-linear relation.

So a smaller voltage does not only decrease power because power is I*V, but also decreases I itself, because I a little bit depends on V too.

Thios is true for all semiconductors. But due to the large numer of influences, this is difficult to calculate.