> Adding a pull-up resistor to the output of the LM358 .. > Say 1k ~ 4k7 or so Thanks for the suggestion. I did some tests Without resistor Supply +5.4 / 0V o/p swing 0 - 4.15V Supply +5.4V / -5.3V o/p swing 0 - 4.14V With resistor (various 1k - 10k) Supply +5.4V / 0V o/p swing 0.915 - 4.80V Supply +5.4V -5.3V o/p swing 0 - 4.80V So a resistor helps, but not quite enough. I suppose you could use 5.4V Vcc with 4/5 gain and have 4.096V out = 5.120V in as an alternative to a higher Vcc > Without it they are awful - can only drive to within 1.5V > of +V (from my memory) According to the d/s that's right. In practice a little closer -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist