Operational Amplifier Topologies and DC Specifications

Operational amplifiers (op amps) are as prolific in analog circuits as salt and pepper is on food. They are sprinkled throughout the sensor data acquisition system, performing a variety of functions. For instance, at the sensor interface, amplifiers are used to buffer and gain the sensor output. The current or voltage excitation to the sensor, quite often is generated by an amplifier circuit. Following the front end sensor circuitry, an op amp is used to implement a low pass, band pass or high pass filter. In this portion of the circuit, gain stages are also implemented using programmable gain amplifiers or instrumentation amplifiers whose building blocks are the op amp. Analog-to-Digital (A/D) converters are most typically driven by an amplifier in order to achieve good converter performance.