Tool/software:
We used an OPA2228UA operational amplifier, with a 5x amplification. The operational amplifier was powered at ± 14V, and a differential component input was added to the preamplifier. We measured the output at pin 1 of the operational amplifier. Under a 5x amplification, it began to decay at 3M. The GBW of this operational amplifier is 33M, and theoretically, it starts to decay at 6M.
Hi Ian,
Under a 5x amplification, it began to decay at 3M. The GBW of this operational amplifier is 33M, and theoretically, it starts to decay at 6M.
It sounds about right. OPA228 has BW of 33MHz at gain of 1V/V. At 5V/V, the BW is reduced to 5.6MHz per GBWP rule. When you add 5.6pF, it will further limiting the op amp's BW to approx. 1.89MHz. If you want to increase the difference amplifier's BW, remove 5.6pF capacitors or change it to 2.2pF or slightly smaller (depending on your BW requirements).
If you have other questions, please let me know.
Best,
Raymond
