In the last edition of Don’t Fear the Filter, we built up two examples of the simplest and most-used active filter of all time: the two-pole Sallen-Key lowpass. This time, we’re going to put two of ...

This article is an excellent introduction to analog filters. It covers the basic first and second order filter types as well as the advantages and disadvantages of passive and active filters. It ...

I was concocting a rather silly low-pass filter design, when I remembered that Messrs Sallen and Key did it better in the 1950s, and decided to use their two-pole design to implement a Butterworth ...

Imperfect Amplifiers, Parasitic Capacitance, And Component Selection All Impact Filter Performance At High Frequencies. Since professors R.P. Sallen and E.L. Key described it in 1955, the Sallen-Key ...

There comes a time in every electronic designer’s life when, whether they know it or not, they need an analog filter in their design. If you’re coming from a digital background, where everything is ...

Michael Steffes challenges conventional approaches to Sallen Key Filter design. He says today's components and VFAs offer greater flexibility. This opinion piece links to more detailed explanations.

Take tunable lowpass filters to new heightsTom Napier, ConsultantWith current output multipliers and fast amplifiers, you can design active lowpass filters whose cutoff frequencies you can ...