Datasheet
December 1990 4
Philips Semiconductors Product specification
4-bit magnitude comparator 74HC/HCT85
APPLICATIONS
• Process controllers
• Servo-motor control
FUNCTION TABLE
Notes
1. H = HIGH voltage level
L = LOW voltage level
X = don’t care
COMPARING INPUTS CASCADING INPUTS OUTPUTS
A
3
, B
3
A
2
, B
2
A
1
, B
1
A
0
, B
0
I
A>B
I
A<B
I
A=B
Q
A>B
Q
A<B
Q
A=B
A
3
>B
3
A
3
<B
3
A
3
=B
3
A
3
=B
3
X
X
A
2
>B
2
A
2
<B
2
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
H
L
H
L
L
H
L
H
L
L
L
L
A
3
=B
3
A
3
=B
3
A
3
=B
3
A
3
=B
3
A
2
=B
2
A
2
=B
2
A
2
=B
2
A
2
=B
2
A
1
>B
1
A
1
<B
1
A
1
=B
1
A
1
=B
1
X
X
A
0
>B
0
A
0
<B
0
X
X
X
X
X
X
X
X
X
X
X
X
H
L
H
L
L
H
L
H
L
L
L
L
A
3
=B
3
A
3
=B
3
A
3
=B
3
A
2
=B
2
A
2
=B
2
A
2
=B
2
A
1
=B
1
A
1
=B
1
A
1
=B
1
A
0
=B
0
A
0
=B
0
A
0
=B
0
H
L
L
L
H
L
L
L
H
H
L
L
L
H
L
L
L
H
A
3
=B
3
A
3
=B
3
A
3
=B
3
A
2
=B
2
A
2
=B
2
A
2
=B
2
A
1
=B
1
A
1
=B
1
A
1
=B
1
A
0
=B
0
A
0
=B
0
A
0
=B
0
X
H
L
X
H
L
H
L
L
L
L
H
L
L
H
H
L
L
Fig.4 Functional diagram.