Op-Amp Gain-Bandwidth Measurement using Impulse Response
John Mark M. Nieva, Glenn V. Magwili, Febus Reidj G. Cruz · 2020
The Gain Bandwidth of an Operational Amplifier (Op-amp) can be measured by sweeping the input frequency signal while monitoring the change in the output signal of the amplifier. This would take considerable test time and can be reduced by implementing a binary search in the test method. However, the binary search method has limited use for multi-channel op-amp tests utilizing a single signal generator. Since parallel testing of multiple channels cannot be achieved using binary searching, the method needs to test each channel serially. In this paper, the Impulse response method was used to measure the Gain Bandwidth of an Op-amp. This method would allow parallel testing of multi-channel op-amp using a single signal generator while maintaining a lower test time. The result shows a test time reduction of about 95.89% compared to the sweep method and 8.45% as compared to the method using a binary search. A t-test was also performed to compare the results of this method to the two preceding methods. Furthermore, improvement using centered difference numerical differentiation was also discussed.