A   B
0 0 1
0 1 1
1 0 1
1 1 0

The NAND gate is a digital logic gate that behaves according to the truth table to the right. A LOW output results only if both the inputs to the gate are HIGH. If one or both inputs are LOW, a HIGH output results.The nand gate is a universal gate in the sense that any boolean function can be implemented by nand gates.

Symbols Edit

There are two symbols for NAND gates: the 'military' symbol and the 'rectangular' symbol. For more information see logic gate symbols.


'Military' NAND symbol


'Rectangular' NAND symbol


Hardware description and pinout Edit

NAND gates are basic logic gates, and as such they are recognised in TTL and CMOS ICs.

File:CMOS 4011 diagram.svg

CMOS version Edit

The standard, 4000 series, CMOS IC is the 4011, which includes four independent, two-input, NAND gates.

Availability Edit

These devices are available from most semiconductor manufacturers such as Fairchild Semiconductor, Philips or Texas Instruments. These are usually available in both through-hole DIL and SOIC format. Datasheets are readily available in most datasheet databases.

The standard 2-, 3-, 4- and 8-input NAND gates are available:

  • CMOS
    • 4011: Quad 2-input NAND gate
    • 4023: Triple 3-input NAND gate
    • 4012: Dual 4-input NAND gate
    • 4068: Mono 8-input NAND gate
  • TTL
    • 7400: Quad 2-input NAND gate
    • 7410: Triple 3-input NAND gate
    • 7420: Dual 4-input NAND gate
    • 7430: Mono 8-input NAND gate

Implementations Edit

The NAND gate is the easiest to manufacture, and also has the property of functional completeness. That is, any other logic function (AND, OR, etc.) can be implemented using only NAND gates. An entire processor can be created using NAND gates alone.

File:NMOS NAND.png
File:PMOS NAND.png
File:TTL npn nand.svg

The PMOS NAND is incorrect. This schematic implements a PMOS NOR gate.

See also Edit

External Links Edit

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