>> The dilemma -->
>> They come in a standard version that works on 5V but its quiescent drain 
>> is
>> 170uA to 300uA
>>
>> However, they now offer an ultra-low standby current version that's rated 
>> at 46
>> to 60 uA quiescent.
>>
>> That's MUCH better for a battery operated device. BUT, the ultra-low Iq 
>> version
>> only works on 3V.
>>
>> Okaaaay, I have a 12V, 7.5Ah system and the PIC's (16F84) voltage is 
>> regulated
>> down to 5V using a 78LS05. Not sure what its standby drain is but must be
>> pretty low as the battery lasts for weeks.
>
>Doesn't the 78LS05 consume about 3 milliamps? You could save some
>current right there using a better regulator on the 5V side.

My thought too. I've been playing with the Linear technology LT3470 switcher 
to get 5V off a high voltage supply. With Debbie's case I would then use a 
linear LDO to get the 3.3V from the 5V - but does the 16F84 have suitable 
input thresholds to use the signal from a 3.3V device? It may be better to 
use a later PIC that will operate at 3.3V and run the whole thing at 3.3V - 
without knowing what else the PIC is attached to. 

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