On 1/23/08, alan smith wrote: > So in searching around....LTC, TI, ADI and a various set of > obsure vendors... > > Seems that the AS7793 is the chip of choice...built in current > source, seems to be the perfect interface to a 3 wire RTD. > Anyone used these before? Seems pretty straight forward to use. I think you mean AD7793. It seems to be a good part even though the speed is a bit slow (but should be fine with RTD application). If you are looking at the performace of AD7793, the other possibility is to look at Silabs C8051F060 which has integrated best-in-class ADC for Microcontrollers (2ch 16bit ADC up to 1Msps). Xiaofan -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist