Op Amp Types
Dual Supply / Single Supply / Rail-to-Rail Op Amps
Op amps can be classified into 3 main types based on the input/output voltage range: Dual Supply, Single Supply, and Rail-to-Rail. The input/output voltage range of each type of op amp is shown below.
Dual Supply Op Amps
Since op amps generally amplify small signals close to 0V, when 0V input is required, in the case of a dual supply op amp VEE must be set to -1.5V or less. For this reason, a negative power supply is often used, and since both positive and negative supplies are required, it is called a dual supply op amp.
Single Supply Op Amps (Ground Sense)
When inputting signals near 0V, a negative voltage is needed if using a dual supply op amp (general purpose), but an op amp that enables input without this negative voltage is called a single supply op amp. It is also referred to as a ground sense op amp since it can operate up to the ground level input signal.
Rail-to-Rail Op Amps (Input/Output Full Swing)
With the recent trend towards energy conservation, a greater number of sets are being driven at low voltages. Op amps also need to operate at low voltages, but if the VCC drops to nearly 5V, a single supply op amp is able to only input 1.5V less than VCC, which can be inconvenient. In contrast, a Rail-to-Rail op amp can operate normally even when the input voltage swings from VEE to VCC.
Because it can input/output over the full supply voltage range (VEE to VCC), it is often called an input/output full swing op amp.
For application circuit examples of various types of op amps, please refer to the application notes using the link below.
The next page defines noise characteristics, which is a major issue with op amps.