Amplifier circuit + Zner Diode Problem

[ahmedjaw]

I have designed a schematic with 3 circuits (same configuration) with ampli ops . at the end of each circuit , i put a 3V zener diode because i inject the signal into a uC .

the problem is that :
- when i don't use the zener diode , the circuits works great
- when i use the zener diode , the +15V becomes deformed (and then my output signal , because i use a offset stage )

i didn't understood this phenomenon !

 

[alexan_e]

Have you tried adding a resistor between the opamp output and zener?

 

[ahmedjaw]

I will try it and see if it solves the problem