Adding offset voltage to MAX4304 VF op-amp

Hi,

I am trying to add offset voltage adjustment to MAX4304 voltage feedback op-amp and couldn't get it to work. I was using the same schematic I was using for AD811 by connecting the offset voltage adjustment to the inverting input. But with MAX4304, I don't see any change in the offset voltage of the output. If I take out R17, I can see voltage change at VR1 viper from ±1.2V I may be doing something wrong here which I am not able to get around it.

Any suggestions?

thanks

Pin 2, the voltage will not change when you turn VR1.
Pin 6, the voltage will change when you turn VR1.

Hi Ron,

Is this specific to this IC or it should be connected to Pin 6 for any op-amp? Because this same design works with other op-amps that I use.

thanks

If the op-amp is working AND if the output is not pushed against the supplies, all amps work the same. If the output is almost +5V to almost -5V then the op-amp input can be not equal.

Op-Amp function is to keep (+input) and (-input) at the same voltage.

Your circuit:
R14 makes (+input) at 0 volts.
If VR1 is at 0V then R17 tries to make (-input) at 0 volts.
The Output will be at 0 volts.

If VR1 is turned and pulls up (plus) a small amount the the inputs are not equal. Because (-input) is higher than (+input) the output must go down. Now R17 & VR1 are pulling up and R15 pulls down, to get (-input) back to 0 volts.