Operational transconductance amplifier. A voltage-to-current amplifier where the output current is proportional to the voltage difference between its inputs. Unlike a standard op-amp, an OTA has a high-impedance output and its transconductance can often be controlled by an external bias current, making it highly useful for voltage-controlled filters and amplifiers.
We used an OTA in the synthesizer design so we could easily sweep the filter cutoff with a control voltage.
OTAs are almost always used without external negative feedback, driving a capacitive load directly.
Also heard as
- operational transconductance amplifier
Do not mix it up with
- Op-amp: An OTA outputs current based on input voltage, while an op-amp outputs voltage based on input voltage.
Related terms
Op-amp
A high-gain electronic voltage amplifier with differential inputs and usually a single output.
Transconductance
The electrical property relating the current output of a device to its voltage input.
Amplifier
A circuit or standalone device that increases the power, voltage, or current of an electrical signal.