IC Power Supply Pin
Almost all integrated circuits (ICs) have at least two pins that connect to the power rails of the circuit in which they are installed. These are known as the IC's power supply pins. However, the labeling of the pins varies by IC family and manufacturer.
| Typical supply pin labeling | ||||
|---|---|---|---|---|
| BJT | FET | |||
| VCC | VDD | V+ | VS+ | Positive supply voltage |
| VEE | VSS | V− | VS− | Negative supply voltage |
The simplest labels are V+ and V−, but internal design and historical traditions have led to a variety of other labels being used. V+ and V− may also refer to the inverting (−) and non-inverting (+) voltage inputs of ICs like op amps.
Sometimes one of the power supply pins will be referred to as ground (abbreviated "GND"). In digital logic, this is nearly always the negative pin; in analog integrated circuits, it is most likely to be a pin intermediate in voltage between the most positive and most negative pins.
While double subscript notation, where subscripted letters denote the difference between two points, uses similar looking placeholders with subscripts, the double letter supply voltage subscript notation is not directly linked (though it may have been an influencing factor).
Read more about IC Power Supply Pin: History, Modern Use
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