OPA134 non-Inverting Op-amp Gain

[gerrittube]

Hi,

I’m working on a filter that is buffered with an OPA134 opamp. It’s actually already working, but the gain is way too high.
I need a gain of 1. I now have a resister to ground of 100 Ohm and a feedback resistor of 10KOhm. In series with the output (to a relatively high impedance device) I have a 50 Ohm resistor.

I cannot simply reduce the value of the feedback resistor, as this will create extra loading of the output.

What are my options to get lower gain?

Regards, Gerrit

 

[stv]

You remove the feedback resistor and instead make a direct connection from output to inverting input.
You remove the resistor to ground and leave the connection open.
(Almost) no current will flow from output to incerting input. There is no additional load.

Look for opamp-buffer circuits online.

 

[rayma]

Yes, but do not include the 50R within the feedback loop.

 

[egellings]

You remove the feedback resistor and instead make a direct connection from output to inverting input.
You remove the resistor to ground and leave the connection open.
(Almost) no current will flow from output to incerting input. There is no additional load.

Look for opamp-buffer circuits online.

Be sure to check that the 134 is unity gain stable; I think it is, but am not certain of that.

 

[rayma]

Yes, it is.

 

[egellings]

You're good to go, then.

 

[tomchr]

See the first figure here: https://electronics-course.com/non-inverting-amplifier

Tom

 

[gerrittube]

Thanks everyone for your help. I made the change and the gain is now just a little below 1, which is fine.
And indeed I seee no problems with stability!

Regards, Gerrit