Programmable active filters based on digital potentiometers

The digital potentiometers are flexible devices allowing many of the applications of the mechanical trimming to be replaced by a solid state solution. In this paper, we address issues related to the use of the digital potentiometers in the active filter design, in order to implement programmable analog functions such as controlling the corner frequency and filter type. Also, we propose here a simple interfacing solution that allows for quickly configuring not only programmable filters, but other common circuits employing I²C digital potentiometers.