At 10:31 AM 9/7/2010, Bob Blick wrote: >What I need is a regulator that gives me 5 volts out for 4 to 6 volts >in. Output current less than 300 mA. When it's off, output needs to be >off and input drain no more than a few tens of microamps. I'm not sure if you have checked out the Microchip MCP1640 family but=20 it might be worth looking at. Absolute max input voltage 6.5Vdc 350mA max o/p current @ 5Vdc with 3.3 Vdc input Total disconnect of the output when shut down. You can either follow that with something like a MCP1700-5 (linear=20 low-dropout regulator) or try some funky stuff with the output enable=20 line for when Vbatt exceeds 5V. I have successfully used the MCP1640B in a product that sleeps for=20 most of its two year shelf life (waking for a couple of ms every 2.4=20 seconds) but is awake for a couple of dozen 6 to 10 hour periods=20 during that two year period. Although I'm only a few months into=20 that two year period, a check of the battery voltage in a couple of=20 units is bang on with what I expected (less than 50mV drop in battery volta= ge). The price is certainly right - less than a buck. dwayne --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .