Application Report SBFA001A – November 2001 FilterPro MFB and Sallen-Key Low-Pass Filter Design Program John Bishop, Bruce Trump, R. Mark Stitt Op-Amp Applications, High Performance Linear Products ABSTRACT Although low-pass filters are vital in modern electronics, their design and verification can be tedious and time consuming. The FilterPro program is designed to aid in the design of low-pass filters implemented with the multiple feedback (MFB) and Sallen-Key topology. This note serves as an operator's manual for FilterPro. Among other issues, it describes the information the designer must enter into the program and what the program delivers. Contents FilterPro Low -Pass Filter Design Program .........................................................................................2 Butterworth (maximally flat magnitude). ..........................................................................................3 Chebyshev (equal ripple magnitude)...............................................................................................3 Bessel (maximally flat time delay). ..................................................................................................3 Summary ........................................................................................................................................5 Butterworth Response.............................................................................................................5 Chebyshev Response .............................................................................................................5 Bessel Response ....................................................................................................................5 Circuit Implementation..............................................................................................................
