On Thu, 23 Apr 2009 07:38:06 -0400, "Olin Lathrop" said: > > Almost 4 volts. > > Not so fast. While this appears to be true for most of the LDOs I've > seen, > it is not guaranteed. The datasheets don't say what happens when the > input > voltage drops below spec. "Low dropout" only refers to the operating > range. > 4V into a 5V regulator is not in the operating range. You're right. After I sent the email I thought about adding an addendum. Thanks for correcting me. "Drop Out" happens when it just ceases operating with the correct output voltage, not afterward. Cheers, Bob -- http://www.fastmail.fm - One of many happy users: http://www.fastmail.fm/docs/quotes.html -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist