Op-amp Substitution Question

[jaykarnik]

I am trying to sense a voltage of around 10mV with the op-amp via the sense resistor to drive the gate of a mosfet in current mirror configuration. So far I had been using the LM6134 as I had them lying around. I have almost used up my supply and am looking for a part replacement.

Is MCP6004 a good replacement?

Thanks,
Jay

I am attaching both datasheets for your review. Kinda a newbie so please help out.

 

[ericgibbs]

hi,
The MCP6004 is only 6Vmax supply compared to the LM6134 24Vmax,, what is the OPA supply voltage.?

 

[jaykarnik]

It is a 5V supply given by a 7805. The thing I am worried about is that a bad opamp may not be able to differentiate 10mV from noise.

 

[ericgibbs]

It is a 5V supply given by a 7805. The thing I am worried about is that a bad opamp may not be able to differentiate 10mV from noise.

hi,
I use the MCP6002 series OK at mV input levels.

The MCP6004 should be OK.

 

[crutschow]

One consideration is the offset voltage of the op amp. The MCP6002 series can have up to 7mV of offset so you either need to add an offset adjustment to the circuit or use an op amp with a lower offset, to measure a 10mV signal.

 

[ericgibbs]

One consideration is the offset voltage of the op amp. The MCP6002 series can have up to 7mV of offset so you either need to add an offset adjustment to the circuit or use an op amp with a lower offset, to measure a 10mV signal.

The OP is asking about the MCP6004 as a replacement for the LM6134.

All the MCP600X's I have used are close to zero offset, even though the d/s gives range of +/-7mV.
Agreed if he has a MCP600x with offset the offset adjust is an easy option