2
Functional Diagram
HC Logic Symbol HCT Logic Symbol
TRUTH TABLE
INPUTS OUTPUT
nA nB nC nD nY
LXXXH
XLXXH
XXLXH
XXXLH
HHHHL
H = High Voltage Level, L = Low Voltage Level, X = Irrelevant
1A
NC
1D
1Y
1
3
4
5
7
1C
GND
1B
2
6
14
12
11
10
8
13
9
V
CC
2C
2B
2A
NC
2Y
2D
nA
nB
nY
nC
nD
nA
nB
nY
nC
nD
CD54HC20, CD74HC20, CD54HCT20, CD74HCT20
