Voltage Controlled Filter AS 3109
                    
                        AS3109 is a high-performance voltage-controlled four-pole filter, pin to pin replacement of IR3109 VCF ICs found on vintage Roland synths, like Jupiter series, Juno series, SH-101, and others. The four independent sections may be interconnected to provide a wide variety of filter responses, such as low pass, high pass, bandpass, and all pass. A single input exponentially controls the frequency over greater than a 15-octave range with little control voltage feedthrough. 
AS3109 comes in SOIC-16 case.