Jinx wrote: >> Does it have to be high-side? Low-side measurement is easier... > > I guess it doesn't have to be high-side. FWIW, I think low side sensing is inherently more precise (with equal precision of the resistors). >> What is the fiddling and twiddling you had to do with opamp designs? >> After all, in your application, the MAX472 is little more than an opamp > > Well, integral designs like the RCV420/INA168/MAX4137 are > factory-trimmed for accuracy. I did miss this feature. So I guess what you want is an opamp with a fixed (and calibrated) amplification? I saw that Maxim offers replacements for the MAX472 -- if you're a lucky guy you might just try these :) Linear also has current sense amps of that type (like the LT1787 or LT6100; I tend to prefer Linear for this sort of thing) for both high side and low side sensing. They also have trimmed-gain resistor amplifiers like the LT1991. Gerhard -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist