CD54HC85 Datasheet, PDF (2/15 Pages) Texas Instruments – High-Speed CMOS Logic 4-Bit Magnitude Comparator

CD54HC85, CD74HC85, CD54HCT85, CD74HCT85
PFunctional Diagram
A3 ¹⁵
A2 ¹³
A1 ¹²
10
A0
2
(A < B) IN
3
(A = B) IN
4
(A > B) IN
1
B3
14
B2
11
B1
9
B0
7
(A < B) OUT
6
(A = B) OUT
5 _{(A > B) OUT}
TRUTH TABLE
COMPARING INPUTS
A3, B3
A2, B2
A1, B1
A0, B0
SINGLE DEVICE OR SERIES CASCADING
A3 > B3
X
X
X
A3 < B3
X
X
X
A3 = B3
A2 >B2
X
X
A3 = B3
A2 < B2
X
X
A3 = B3
A2 = B2
A1 > B1
X
A3 = B3
A2 = B2
A1 < B1
X
A3 = B3
A2 = B2
A1 = B1
A0 > B0
A3 = B3
A2 = B2
A1 = B1
A0 < B0
A3 = B3
A2 = B2
A1 = B1
A0 = B0
A3 = B3
A2 = B2
A1 = B1
A0 = B0
A3 = B3
A2 = B2
A1 = B1
A0 = B0
PARALLEL CASCADING
A3 = B3
A2 = B2
A1 = B1
A0 = B0
A3 = B3
A2 = B2
A1 = B1
A0 = B0
A3 = B3
A2 = B2S
A1 = B1
A0 = B0
H = High Voltage Level, L = Low Voltage, Level, X = Don’t Care
CASCADING INPUTS
A>B
A<B
A=B
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
H
L
L
L
H
L
L
L
H
X
X
H
H
H
L
L
L
L
OUTPUTS
A>B
A<B
A=B
H
L
L
L
H
L
H
L
L
L
H
L
H
L
L
L
H
L
H
L
L
L
H
L
H
L
L
L
H
L
L
L
H
L
L
H
L
L
L
H
H
L
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