with an external control voltage, the gain of the signal path can be modulated dynamically.
The is a specialized version of the operational amplifier where the output is a current proportional to the differential input voltage . Unlike standard op-amps that act as voltage-controlled voltage sources (VCVS), the OTA acts as a voltage-controlled current source (VCCS) . 1. Distinguish between standard Op-Amps and OTAs Op–Amp Circuits Manual. Including OTA Circuits
: A standard op-amp (e.g., 741) provides a voltage output with low output impedance, while an OTA (e.g., CA3080) provides a current output with high output impedance . with an external control voltage, the gain of
: Standard op-amps almost always use negative feedback to set a fixed gain. In contrast, OTAs are often used in open-loop configurations because the output current is naturally limited by the bias current, preventing saturation in many applications. 2. Understand the Transfer Function In contrast, OTAs are often used in open-loop
The fundamental relationship governing an OTA is defined by its transconductance, which relates the output current ( Ioutcap I sub o u t end-sub ) to the differential input voltage (
to zero, OTAs function as excellent electronic switches or gated amplifiers.
Iout=gm×(Vin+−Vin−)cap I sub o u t end-sub equals g sub m cross open paren cap V sub i n end-sub raised to the positive power minus cap V sub i n end-sub raised to the negative power close paren