Quoting RussellMc : > I've never used an MC78LCxx regulator BUT from ON Semiconductor it's > about certain that you can rely on what the datasheet says. Care needs > to be taken that you know how o interpret a given datasheet figure. > Many people often don't. > > The question with reputable manufacturers is usually not "are they > telling the truth" but "do I understand what they are saying". Thanks for confirming they are reliable, someone else had said so =20 privately. With that established, my question was absolutely =20 concerning my understanding! I will order a few and test with a real battery (rechargeable CR123A =20 @3.6v) and sample circuit (PIC waking a few times an hour for sensor =20 readings). The alternative of course is a PIC that has a wider Vdd range (e.g. =20 2.7v to 5.5v) and a switched LDO (through a FET) for the sensors, =20 rather than powering everything through the LDO. Comments on this =20 would be welcome, the new nanowatt parts have pretty impressive =20 characteristics. The reason I worry about an LDO at all is because it seems silly to =20 spend upwards of $20 on a sensor and not power it from a properly =20 regulated source. Indeed the SHT71 conversion/compensation routines =20 rely on knowing voltages in some cases. Your second post regarding testing is also excellent, thank you. David --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .