ALFA RPAR AS3350 IC - CEM3350 Replacement
The AS 3350 is a dual voltage controlled state-variable filter intended for electronic musical instruments and other signal processing applications. Each filter provides both voltage control of center/cut-off frequency over more than 12 octaves and voltage control of Q from 1/2 to greater than 40. All control scales are exponential, allowing for easier control of the parameters over their wide range. Although the two filters are completely independent, they may be easily interconnected to form a wide variety of filter responses. Each filter also provides two signal inputs: For signals applied to the fixed gain input, the output will remain constant as the Q is varied, while for signals applied to the variable gain input, the output decreases as Q is increased. The input signal may be proportioned between these two inputs to provide any desired characteristic. Finally, each filter provides two simultaneous outputs, making directly available low-pass and band-pass, or bandpass and high-pass responses depending upon where the input signal is applied. Able to operate over a wide supply range, the versatile AS 3350 allows new and unique filter responses to be created with a high degree of voltage control over the defining parameters.
The AS3350 is available in DIP16 thru-hole, SOIC16 SMT configurations
Datasheet: http://www.alfarzpp.lv/eng/sc/AS3350.pdf
Here is a wonderful Wikipedia page that lists original CEM and SSM chips in synthesizers to help with replacment decisions: https://en.wikipedia.org/wiki/CEM_and_SSM_chips_in_synthesizers