Digital Electronics Series
NAND Gate: Universal Logic
Truth Table, CMOS Implementation & VLSI Importance
NAND Gate Logic Simulator
A
B
Y
1
Toggle A and B to see why NAND only outputs 0 when both are 1.
The NAND gate is a universal gate, meaning any logic function (AND, OR, NOT, etc.) can be implemented using only NAND gates. In CMOS technology, it is physically smaller and faster than an equivalent AND gate.
01 Truth Table
| Input A | Input B | Output Y |
|---|---|---|
| 0 | 0 | 1 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 0 |
Boolean Expression
Y = \overline{A \cdot B}
Why NAND Rules VLSI
Faster Switching
NAND structures have lower parasitic capacitance compared to NOR, leading to higher performance.
Lower Density
Requires fewer transistors and smaller silicon area than AND gates in standard CMOS libraries.
ASIC Preferred
Because it’s “complete,” designers can map any logic to a grid of NAND gates for easier fabrication.