OPA855: Is this Op-amp capable of driving output to 0V ?

Hello Ganesh,

The OPA855 is not a rail-to-rail amp. Unfortunately I was not able to find a replacement that is rail-to-rail and the same package type. If you can accommodate a different package, let me know and I'll look for it.

If you are able to configure the system in split supply instead, you could get a 0V output without switching the part.

There were a couple other things I wanted to mention about the design you sent. This part is decompensated, and has a minimum stable gain of 7 V/V. Stabilizing it at a lower gain is possible but will take more design. If you are replacing the part and need the 3 V/V gain you showed, look for a unity gain stable part.

Also note that the datasheet recommends an Rf = 453Ω. Using a resistor that's much higher, like 20kΩ, may interact with the input capacitance of the amp and destabilize the system. It will also increase noise and worsen some other datasheet specs. I would suggest using something more on the magnitude of the suggested Rf if possible.

Let me know if you have any questions or if I can help with anything else.

All the best,

Hypatia

Hi Hypatia,

Thank you for your response. Assuming I make the circuit stable with R1=100 ohms and Rf=700 ohms with a closed loop gain of 7 V/V, What is the lowest voltage the OPA855 can drive in this schematic configuration?

Regards,

Ganesh

Thank you !