David wrote:

> The alternative of course is a PIC that has a wider Vdd range (e.g.
> 2.7v to 5.5v) and a switched LDO (through a FET) for the sensors,
> rather than powering everything through the LDO.  Comments on this
> would be welcome, the new nanowatt parts have pretty impressive
> characteristics.

I don't know the sensor you're using, but whether this makes sense
depends in part on the sensor.=20

FWIW, if the PIC's Vdd range matches your battery, I don't see a reason
why you'd have to power the PIC through a regulator -- unless you want
to use that regulator as ADC reference and can't use the external
reference pins for that.

I'm not a low power specialist, but powering the PIC directly from the
battery and powering external circuitry from PIC pins (or through
switched FETs) seems to be a standard measure to keep the power
consumption during sleep times minimal.

Gerhard
--=20
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