An OTA amplifier is a type of operational amplifier, except that the OTA amplifier has an extremely high impedanceoutput
and behaves like a current source. An OTA amplifier converts the input voltage into an output current. This characteristic is equivalent to that of a transconductance. This is defined by the ratio of the output current to the input voltage.
OTA amplifiers are used in audio compression circuits and audio limiter circuits because they have a higher rate of change and thus significantly improve the compressor dynamics compared to voltage controlled amplifiers (VCA).