I am thinking of using a microcontroller (perhaps a PIC) in an industrial
 project.
The controller would have to interface with  0 to 20mA analogue input and
output signals.  Does anybody know of an IC(s) that does current-to-voltage
conversion and vica versa, perhaps with the use of one or two passive
components?  I am looking for alternatives to using opamps.

Any suggestions/comments/advice appreciated.

Hennie Swanepoel