Looking at a Fairchild FAN1589, its a 2.7A LDO, 1.2V
out device.

Given the formula in the datasheet that Pd=
(Vin-Vout)*Iout, I have a 3.3V source, 800mA load.

In calculations then, it comes out to be 1.68W
dissipation.  Not too bad.  So given that the load is
0.96W, adding the Pd gives about 2.64W.

All this is being done to calculate the load for the
source supply...so I would imagine 2.64W or 800mA.

Well, one never to trust calculations always I wired
it up and what did I find...1200mA or nearly 4W being
pulled on the device.  Pretty far off for just a error
in mesurement.

Am i missing something in my analysis?

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