Cancellation Technique of Parasitics in Active Filter Design

Takao TSUKUTAKI  Masaru ISHIDA  Yutaka FUKUI  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E76-A    No.6    pp.957-960
Publication Date: 1993/06/25
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section LETTER (Special Section on Papers Selected from 1992 Joint Technical Conference on Circuits/Systems,Computers and Communications (JTC-CSCC'92))
Category: Methods and Circuits for Signal Processing
active filters,  operational amplifiers,  parasitics,  highpass characteristics,  

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This letter presents a technique to cancel the parasitic effects of operational amplifier (op amp) in active filter design. To minimize the effects, an op amp model considering the parasitics (i.e. both parasitic poles and zeros) is utilized. It is shown that undesirable factors in the transfer function due to the parasitics can be canceled well by predistorting the passive element values of the circuit. As an example, an active-R highpass filter is evaluated both theoretically and numerically. In this way, the proposed technique can be effectively incorporated into the design of active filters.