Like all widely-used devices, numerous common terms have developed that are unique to this type of device. These terms include:
- Fully differential amplifier (FDA)—In this document, this term is restricted to devices offering what appears similar to a differential inverting op amp design element that requires an input resistor (not high-impedance input) and includes a second internal control-loop setting the output average voltage (Vocm) to a default or set point. This second loop interacts with the differential loop in some configurations.
- The desired output signal at the two output pins is a differential signal swinging symmetrically around a common-mode voltage where that is the average voltage for the two outputs.
- Single-ended to differential—always use the outputs differentially in an FDA; however, the source signal can be either a single-ended source or differential, with a variety of implementation details for either. When the FDA operation is single-ended to differential, only one of the two input resistors receives the source signal with the other input resistor connected to a DC reference (often ground) or through a capacitor to ground.