Not Connected Pin (NC pin) or Not Connected Terminals are pins found on various integrated circuit packages. Those pins have no functional purpose to the outside circuit. Those pins should not be connected to any of your circuit connections (apart from power rails).

IC chips are mostly mass produced in a limited array of packages. Most designers are thus restricted to one of those pre-defined packages. Sometimes the device that's designed does not utilize all the pins for various reasons. When that happens, those pins gets labeled "NC" or "Not Connected".

Use in EDA

When designing circuits (e.g. for PCBs), marking NC pins correctly is very important because many of those tools with Electrical Rule Check capabilities can detect when something is mistakenly connected to them thereby issuing a warning.

See also

• pinout
• power-supply pin
• IC package