The INA330 is a precision amplifier designed for thermoelectric cooler (TEC) control in optical networking applications. It is optimized for use in 10k thermistor-based temperature controllers. The INA330 provides thermistor excitation and generates an output voltage proportional to the difference in resistances applied to the inputs. It uses only one precision resistor plus the thermistor, thus providing an alternative to the traditional bridge circuit. This new topology eliminates the need for two precision resistors while maintaining excellent accuracy for temperature control applications.

An excitation voltage is applied to the thermistor (R_THERM) and precision resistor (R_SET), creating currents I₁ and I₂. The current conveyor circuit produces an output current, I₀, equal to I₁ – I₂, which flows through the external gain-setting resistor.