INTEGRATED CIRCUITS
DATA SHEET
For a complete data sheet, please also download:
•
The IC06 74HC/HCT/HCU/HCMOS Logic Family Specifications
•
The IC06 74HC/HCT/HCU/HCMOS Logic Package Information
•
The IC06 74HC/HCT/HCU/HCMOS Logic Package Outlines
74HC/HCT688
8-bit magnitude comparator
Product specification
File under Integrated Circuits, IC06
December 1990
Philips Semiconductors
Product specification
8-bit magnitude comparator
FEATURES
•
Compare two 8-bit words
•
Output capability: standard
•
I
CC
category: MSI
GENERAL DESCRIPTION
74HC/HCT688
The 74HC/HCT688 are high-speed Si-gate CMOS devices
and are pin compatible with low power Schottky TTL
(LSTTL). They are specified in compliance with JEDEC
standard no. 7A.
The 74HC/HCT688 are 8-bit magnitude comparators.
They perform comparison of two 8-bit binary or BCD
words.
The output provides P = Q.
QUICK REFERENCE DATA
GND = 0 V; T
amb
= 25
°C;
t
r
= t
f
= 6 ns
TYPICAL
SYMBOL
t
PHL/
t
PLH
PARAMETER
propagation delay
P
n
, Q
n
to P = Q
E to P = Q
C
I
C
PD
Notes
1. C
PD
is used to determine the dynamic power dissipation (P
D
in
µW):
P
D
= C
PD
×
V
CC2
×
f
i
+ ∑
(C
L
×
V
CC2
×
f
o
)
f
i
= input frequency in MHz
f
o
= output frequency in MHz
∑
(C
L
×
V
CC2
×
f
o
) = sum of outputs
C
L
= output load capacitance in pF
V
CC
= supply voltage in V
2. For HC the condition is V
I
= GND to V
CC
For HCT the condition is V
I
= GND to V
CC
−
1.5 V
ORDERING INFORMATION
See
“74HC/HCT/HCU/HCMOS Logic Package Information”.
where:
input capacitance
power dissipation capacitance per package
notes 1 and 2
CONDITIONS
HC
C
L
= 15 pF; V
CC
= 5 V
17
8
3.5
30
17
12
3.5
30
ns
ns
pF
pF
HCT
UNIT
December 1990
2
Philips Semiconductors
Product specification
8-bit magnitude comparator
PIN DESCRIPTION
PIN NO.
1
2, 4, 6, 8, 11, 13, 15, 17
3, 5, 7, 9, 12, 14, 16, 18
10
19
20
SYMBOL
E
P
0
to P
7
Q
0
to Q
7
GND
P=Q
V
CC
NAME AND FUNCTION
enable input (active LOW)
word inputs
word inputs
ground (0 V)
equal to output
positive supply voltage
74HC/HCT688
Fig.1 Pin configuration.
Fig.2 Logic symbol.
Fig.3 IEC logic symbol.
December 1990
3
Philips Semiconductors
Product specification
8-bit magnitude comparator
74HC/HCT688
Fig.4 Functional diagram.
Fig.5 Logic diagram.
FUNCTION TABLE
INPUTS
DATA P
n
, Q
n
P=Q
X
P
>
Q
P
<
Q
Notes
1. H = HIGH voltage level
L = LOW voltage level
X = don’t care
ENABLE E
L
H
L
L
OUTPUT
P=Q
L
H
H
H
December 1990
4
Philips Semiconductors
Product specification
8-bit magnitude comparator
DC CHARACTERISTICS FOR 74HC
For the DC characteristics see
“74HC/HCT/HCU/HCMOS Logic Family Specifications”.
Output capability: standard
I
CC
category: MSI
AC CHARACTERISTICS FOR 74HC
GND = 0 V; t
r
= t
f
= 6 ns; C
L
= 50 pF
T
amb
(°C)
74HC
SYMBOL PARAMETER
min.
t
PHL
/ t
PLH
propagation delay
P
n
, Q
n
to P = Q
propagation delay
E to P = Q
output transition time
+25
typ.
55
20
16
28
10
8
19
7
6
max.
170
34
29
120
24
20
75
15
13
−40
to
+85
min.
max.
215
43
37
150
30
26
95
19
16
−40
to
+125
min.
max.
255
51
43
180
36
31
110
22
19
ns
74HC/HCT688
TEST CONDITIONS
UNIT
V
CC
WAVEFORMS
(V)
2.0
4.5
6.0
2.0
4.5
6.0
2.0
4.5
6.0
Fig.6
t
PHL
/ t
PLH
Fig.7
ns
t
THL
/ t
TLH
Figs 6 and 7
ns
December 1990
5
