Page 33 - DCAP108_DIGITAL_CIRCUITS_AND_LOGIC_DESIGNS

Digital Circuits and Logic Design

Notes
Figure 2.18: Expanding XOR Inputs

The most famous XOR gate integrated circuit is 7486 and you can its pinout in Figure 2.19.
Figure 2.19: 7486 Integrated Circuit Provides Four Two-Inputs XOR Gates

2.1.7 XNOR Gate
XNOR stands for exclusive NOR and is an XOR gate with its output inverted. So, its output is
at ”1“ when the inputs have the same value and ”0“ when they are different. XNOR operation
is represented by the symbol (•). So Y = A (•) B. You can see XNOR logic gate symbol in
Figure 2.20 and its truth table right below it.
Figure 2.20: XNOR Logic Gate

Table 2.7: Truth Table

A B Y
0 0 1
0 1 0
1 0 0
1 1 1

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