The AS3320 is a high-performance voltage-controlled four-pole filter with an on-chip voltage controllable resonance IC. 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. It is a replacement for the Curtis 3320 IC, which was used in many iconic analog synthesizers including designs by he Digisound-80 Modular System, Elka Synthex, Fairlight CMI II/IIx, LinnDrum, Oberheim,PPG Wave, Sequential Circuits synths, and many more. The datasheet is here: AS3320
