Universal Current-Mode OTA-C KHN Biquad

A universal current-mode biquad is described which represents an economical variant of well-known KHN (Kerwin, Huelsman, Newcomb) voltage-mode filter. The circuit consists of two multiple-output OTAs and of two grounded capacitors. Utilizing simple splitter of the input current and a pair of jumpers, all the basic 2-order transfer functions can be implemented. The principle is verified by Spice simulation on the level of a CMOS structure of OTAs. Keywords—Biquad, current mode, OTA.