Compensation techniques for gain-bandwidth effects of active RC filters

The gain-bandwidth (GB) product of an operational amplifier (op amp) can effect the filtering characteristics of an infinite gain, multiple feedback, low pass active RC filter. In this thesis, the characteristics of ideal op amps and actual op amps are compared. The op amp is characterized by a dominant single pole, which is used to develop a third order voltage transfer function that describes the op amp's gain-bandwidth effects on the filter. Optimization theory is used to find adjusted values for the filter's elements to compensate for these GB effects. Of the sixty-five compensation design methods examined with the optimization program GOSPEL, twelve methods produced useful compensation results. The adjusted element values are tabulated and displayed in design graphs for several values of GB and quality factor, Q. The twelve design techniques were verified by simulating the filter with the adjusted element values using PSpice