Using a Microchip 602ISN on a board I have. Pretty simple little unit, 5V supply, rail-to-rail, set up to bring in X volts and spit out X volts with more power behind it.
The + and - are tied togather with the output being read by my pic's adc. So for example 4.00V comes in from another systems volt-drop resistor switch tree (figure .05mA or so), goes into the amp, comes out and goes into the pic with a 1k resistor inbetween. So my pic's adc gets a higher strength sample.
When I tested in prototyping it worked fine. But other day I had a strange problem and come to find out that the opAmp is only working corrently for signals around 4V, nothing higher. For example:
.9V > .9V
3V > 3V
4V > 4V
4.5V > 5V
5V > 5V
I'm not sure what could have damaged the unit, or if I picked a finicky model, or whatever.
Its confusing me since it apprears to be pass 4.5V signals right to VSS.
Any ideas ?
The + and - are tied togather with the output being read by my pic's adc. So for example 4.00V comes in from another systems volt-drop resistor switch tree (figure .05mA or so), goes into the amp, comes out and goes into the pic with a 1k resistor inbetween. So my pic's adc gets a higher strength sample.
When I tested in prototyping it worked fine. But other day I had a strange problem and come to find out that the opAmp is only working corrently for signals around 4V, nothing higher. For example:
.9V > .9V
3V > 3V
4V > 4V
4.5V > 5V
5V > 5V
I'm not sure what could have damaged the unit, or if I picked a finicky model, or whatever.
Its confusing me since it apprears to be pass 4.5V signals right to VSS.
Any ideas ?