Operational transconductance amplifier

An operational transconductance amplifier (OTA) is an amplifier whose differential input voltage produces an output current.

OTAs used in synths

 * CA3080
 * CEM3320
 * CEM3328
 * CEM3389
 * CEM3379
 * IR3109
 * LM13700 and LM13600
 * SSM2040
 * SSM2044

DIY OTA
OTA can be made from matched-pair BJTs.

Data sheets

 * Operational Transconductance Amplifiers (OTA) at Aaron D. Lanterman's Synth DIY Datasheet and Ap Note Collection (Archive.org)

Projects

 * VCF-1 by Thomas Henry