>>That's up to you. If you would use a production programmer you 
>>should
>>set the extremes at the tolerances of the regulator, probably 4.5 
>>and
>>5.5 Volt.

> I very much doubt that the 7805 family (just to name the most 
> probable
> regulator used) has a 1000 mV tolerance..

Pretty close !!! / You may be surprised.

The 7805 / LM340 is not a nice regulator by modern standards.
It's +/- 0.35v for 8v < Vin  < 20v and load range 5 ma - 1 A.
The former is PROBABLY not likely, depending on application and the 
latter is quite possible during some systems' extremes. That's at the 
regulator, of course, leaving you 0.15v leeway to where-ever the "5v" 
goes. How much drop you get at the PIC depends on your design.

And the above is NOT including variation with junction temperature. 
Throw that in as well and you can probably expect some designs to meet 
the + or - 0.5v excursion from nominal. Not every design, but you do 
need to be sure that it's not your one if you haven't tested the 
processors at the extremes of possible voltage.



                RM

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist