LTC1728 has tolerance of 0.05% www.linear.com/go/1389 Andre Abelian -----Original Message----- > I am planning to read some 0.5V to 4.5V sensor > voltages, and need good 0.5V and 4.5V precission > references. I plan to use Analog Devices REF194 > to get the 4.5V, but don't know how to get the > 0.5V without using resistors, op-amps, etc. Use ground as the lower reference. Do you really need the extra precision from a 4V range instead of a 4.5V range? ***************************************************************** Embed Inc, embedded system specialists in Littleton Massachusetts (978) 742-9014, http://www.embedinc.com -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.