AS3109D VCF SOIC 16

AS3109 is a high performance voltage controlled four-pole filter. The four independent sections may be interconnected to provide a wide variety of filter responses, such as low pass, high pass, band pass and all pass. A single input exponentially controls the frequency over greater than a 15 octave range with little control voltage feedthrough. AS3109 benefits from high input impedance buffers.

https://www.alfarzpp.lv/eng/sc/AS3109.pdf