Electronic – Rail-to-rail oscillations in subtractor op amp circuit

operational-amplifieroscillationoutput

schematic

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Just bumped into a problem. When I am trying to make a voltage subtractor based on AD8055 op Amplifier, I get rail-to-rail oscillations/noise one the output.

The signal is 0.5sin + 1.5V at 1MHz. I wish to shift down the signal to 0.5sin + 0.5.
Any ideas why I do not get a desired output?

Edit:
enter image description here

Best Answer

This is a pretty fast op-amp. It's almost certainly due to layout or decoupling.

Do you have ceramic decoupling caps right at the supply inputs to a ground plane? Is this on a PCB with short traces and a tight layout or is it on a breadboard?

If it's the latter you might want to try a lower bandwidth op-amp. Since your differential gain is 1 but your noise gain is 2, you need an amplifer with a gain bandwidth of say 10MHz or so. (Assuming the 1MHz signal is the highest frequency you need to work with.)

This is a 300MHz amplifier, which is probably making your life more difficult than it needs to be.