Leap-frog circuit compensating influence of GB product and secondpole of operational amplifier

摘要

The paper describes a method by which a high frequency leap-frognfilter which simulates an LC filter is designed. First, taking accountnof the finite gain bandwidth product and the second pole of annoperational amplifier, we analyse the frequency characteristics of anconventional inverting integrator. Second, we analyse the frequencyncharacteristic of a phase-lead noninverting integrator and show thendesign formulas which give the element values to compensate phase lag ofnthe inverting integrator. Finally, a fifth-order Chebyshev filter havingna 1 dB pass-band ripple is designed. The operational amplifiers whichnhave a gain-bandwidth product of f=5.33 MHz are used, and the cut-offnfrequency is set to 533 kHz (a tenth of the value of the GB product). Itnis shown that the measured response shows a good agreement with thentheoretical value