Document Outline
- FEATURES
- GENERAL DESCRIPTION
- QUICK REFERENCE DATA
- ORDERING INFORMATION
- PIN DESCRIPTION
- FUNCTION TABLE
- DC CHARACTERISTICS
- AC CHARACTERISTICS
- AC WAVEFORMS
- APPLICATION INFORMATION
- PACKAGE OUTLINES
DATA SHEET
Product specification
File under Integrated Circuits, IC06
December 1990
INTEGRATED CIRCUITS
74HC/HCT688
8-bit magnitude comparator
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
December 1990
2
Philips Semiconductors
Product specification
8-bit magnitude comparator
74HC/HCT688
FEATURES
Compare two 8-bit words
Output capability: standard
I
CC
category: MSI
GENERAL DESCRIPTION
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
Notes
1. C
PD
is used to determine the dynamic power dissipation (P
D
in
W):
P
D
= C
PD
V
CC
2
f
i
+
(C
L
V
CC
2
f
o
)
where:
f
i
= input frequency in MHz
f
o
= output frequency in MHz
(C
L
V
CC
2
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"
.
SYMBOL
PARAMETER
CONDITIONS
TYPICAL
UNIT
HC
HCT
t
PHL/
t
PLH
propagation delay
C
L
= 15 pF; V
CC
= 5 V
P
n
, Q
n
to P = Q
17
17
ns
E to P = Q
8
12
ns
C
I
input capacitance
3.5
3.5
pF
C
PD
power dissipation capacitance per package
notes 1 and 2
30
30
pF
December 1990
3
Philips Semiconductors
Product specification
8-bit magnitude comparator
74HC/HCT688
PIN DESCRIPTION
PIN NO.
SYMBOL
NAME AND FUNCTION
1
E
enable input (active LOW)
2, 4, 6, 8, 11, 13, 15, 17
P
0
to P
7
word inputs
3, 5, 7, 9, 12, 14, 16, 18
Q
0
to Q
7
word inputs
10
GND
ground (0 V)
19
P = Q
equal to output
20
V
CC
positive supply voltage
Fig.1 Pin configuration.
Fig.2 Logic symbol.
Fig.3 IEC logic symbol.
December 1990
4
Philips Semiconductors
Product specification
8-bit magnitude comparator
74HC/HCT688
FUNCTION TABLE
Notes
1. H = HIGH voltage level
L = LOW voltage level
X = don't care
INPUTS
OUTPUT
DATA P
n
, Q
n
ENABLE E
P = Q
P = Q
X
P
>
Q
P
<
Q
L
H
L
L
L
H
H
H
Fig.4 Functional diagram.
Fig.5 Logic diagram.
December 1990
5
Philips Semiconductors
Product specification
8-bit magnitude comparator
74HC/HCT688
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
SYMBOL
PARAMETER
T
amb
(
C)
UNIT
TEST CONDITIONS
74HC
V
CC
(V)
WAVEFORMS
+
25
-
40 to
+
85
-
40 to
+
125
min.
typ.
max.
min.
max.
min.
max.
t
PHL
/ t
PLH
propagation delay
P
n
, Q
n
to P = Q
55
20
16
170
34
29
215
43
37
255
51
43
ns
2.0
4.5
6.0
Fig.6
t
PHL
/ t
PLH
propagation delay
E to P = Q
28
10
8
120
24
20
150
30
26
180
36
31
ns
2.0
4.5
6.0
Fig.7
t
THL
/ t
TLH
output transition time
19
7
6
75
15
13
95
19
16
110
22
19
ns
2.0
4.5
6.0
Figs 6 and 7
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