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Электронный компонент: DM54LS85

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TL F 6379
54LS85DM54LS85DM74LS85
4-Bit
Magnitude
Comparators
June 1989
54LS85 DM54LS85 DM74LS85
4-Bit Magnitude Comparators
General Description
These 4-bit magnitude comparators perform comparison of
straight binary or BCD codes Three fully-decoded decisions
about two 4-bit words (A B) are made and are externally
available at three outputs These devices are fully expand-
able to any number of bits without external gates Words of
greater length may be compared by connecting compara-
tors in cascade The A
l
B A
k
B and A
e
B outputs of a
stage handling less-significant bits are connected to the cor-
responding inputs of the next stage handling more-signifi-
cant bits The stage handling the least-significant bits must
have a high-level voltage applied to the A
e
B input The
cascading path is implemented with only a two-gate-level
delay to reduce overall comparison times for long words
Features
Y
Typical power dissipation 52 mW
Y
Typical delay (4-bit words) 24 ns
Y
Alternate Military Aerospace device (54LS85) is avail-
able Contact a National Semiconductor Sales Office
Distributor for specifications
Connection Diagram
Dual-In-Line Package
TL F 6379 1
Order Number 54LS85DMQB
54LS85FMQB 54LS85LMQB
DM54LS85J DM54LS85W
DM74LS85M or DM74LS85N
See NS Package Number E20A
J16A M16A N16E or W16A
Function Table
Comparing
Cascading
Outputs
Inputs
Inputs
A3 B3
A2 B2
A1 B1
A0 B0
A
l
B
A
k
B
A
e
B
A
l
B
A
k
B
A
e
B
A3
l
B3
X
X
X
X
X
X
H
L
L
A3
k
B3
X
X
X
X
X
X
L
H
L
A3
e
B3
A2
l
B2
X
X
X
X
X
H
L
L
A3
e
B3
A2
k
B2
X
X
X
X
X
L
H
L
A3
e
B3
A2
e
B2
A1
l
B1
X
X
X
X
H
L
L
A3
e
B3
A2
e
B2
A1
k
B1
X
X
X
X
L
H
L
A3
e
B3
A2
e
B2
A1
e
B1
A0
l
B0
X
X
X
H
L
L
A3
e
B3
A2
e
B2
A1
e
B1
A0
k
B0
X
X
X
L
H
L
A3
e
B3
A2
e
B2
A1
e
B1
A0
e
B0
H
L
L
H
L
L
A3
e
B3
A2
e
B2
A1
e
B1
A0
e
B0
L
H
L
L
H
L
A3
e
B3
A2
e
B2
A1
e
B1
A0
e
B0
L
L
H
L
L
H
A3
e
B3
A2
e
B2
A1
e
B1
A0
e
B0
X
X
H
L
L
H
A3
e
B3
A2
e
B2
A1
e
B1
A0
e
B0
H
H
L
L
L
L
A3
e
B3
A2
e
B2
A1
e
B1
A0
e
B0
L
L
L
H
H
L
H
e
High Level L
e
Low Level X
e
Don't Care
C1995 National Semiconductor Corporation
RRD-B30M105 Printed in U S A
Absolute Maximum Ratings
(Note)
If Military Aerospace specified devices are required
please contact the National Semiconductor Sales
Office Distributors for availability and specifications
Supply Voltage
7V
Input Voltage
7V
Operating Free Air Temperature Range
DM54LS and 54LS
b
55 C to
a
125 C
DM74LS
0 C to
a
70 C
Storage Temperature Range
b
65 C to
a
150 C
Note
The ``Absolute Maximum Ratings'' are those values
beyond which the safety of the device cannot be guaran-
teed The device should not be operated at these limits The
parametric values defined in the ``Electrical Characteristics''
table are not guaranteed at the absolute maximum ratings
The ``Recommended Operating Conditions'' table will define
the conditions for actual device operation
Recommended Operating Conditions
Symbol
Parameter
DM54LS85
DM74LS85
Units
Min
Nom
Max
Min
Nom
Max
V
CC
Supply Voltage
4 5
5
5 5
4 75
5
5 25
V
V
IH
High Level Input Voltage
2
2
V
V
IL
Low Level Input Voltage
0 7
0 8
V
I
OH
High Level Output Current
b
0 4
b
0 4
mA
I
OL
Low Level Output Current
4
8
mA
T
A
Free Air Operating Temperature
b
55
125
0
70
C
Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted)
Symbol
Parameter
Conditions
Min
Typ
Max
Units
(Note 1)
V
I
Input Clamp Voltage
V
CC
e
Min I
I
e b
18 mA
b
1 5
V
V
OH
High Level Output
V
CC
e
Min I
OH
e
Max
DM54
2 5
3 4
V
Voltage
V
IL
e
Max V
IH
e
Min
DM74
2 7
3 4
V
OL
Low Level Output
V
CC
e
Min I
OL
e
Max
DM54
0 25
0 4
Voltage
V
IL
e
Max V
IH
e
Min
DM74
0 35
0 5
V
I
OL
e
4 mA V
CC
e
Min
DM74
0 25
0 4
I
I
Input Current
Max
V
CC
e
Max
A
k
B
0 1
Input Voltage
V
I
e
7V
A
l
B
0 1
mA
Others
0 3
I
IH
High Level Input
V
CC
e
Max
A
k
B
20
Current
V
I
e
2 7V
A
l
B
20
m
A
Others
60
I
IL
Low Level Input
V
CC
e
Max
A
k
B
b
0 4
Current
V
I
e
0 4V
A
l
B
b
0 4
mA
Others
b
1 2
I
OS
Short Circuit
V
CC
e
Max
DM54
b
20
b
100
mA
Output Current
(Note 2)
DM74
b
20
b
100
I
CC
Supply Current
V
CC
e
Max (Note 3)
10
20
mA
Note 1
All typicals are at V
CC
e
5V T
A
e
25 C
Note 2
Not more than one output should be shorted at a time and the duration should not exceed one second
Note 3
I
CC
is measured with all outputs open A
e
B grounded and all other inputs at 4 5V
2
Switching Characteristics
at V
CC
e
5V and T
A
e
25 C (See Section 1 for Test Waveforms and Output Load)
From
To
Number of
R
L
e
2 kX
Symbol
Parameter
Input
Output
Gate Levels
C
L
e
15 pF
C
L
e
50 pF
Units
Min
Max
Min
Max
t
PLH
Propagation Delay Time
Any A or B
A
k
B
3
36
42
Low-to-High Level Output
Data Input
A
l
B
ns
A
e
B
4
40
40
t
PHL
Propagation Delay Time
Any A or B
A
k
B
3
30
40
High-to-Low Level Output
Data Input
A
l
B
ns
A
e
B
4
30
40
t
PLH
Propagation Delay Time
A
k
B
A
l
B
1
22
26
ns
Low-to-High Level Output
or A
e
B
t
PHL
Propagation Delay Time
A
k
B
A
l
B
1
17
26
ns
High-to-Low Level Output
or A
e
B
t
PLH
Propagation Delay Time
A
e
B
A
e
B
2
20
25
ns
Low-to-High Level Output
t
PHL
Propagation Delay Time
A
e
B
A
e
B
2
17
26
ns
High-to-Low Level Output
t
PLH
Propagation Delay Time
A
l
B
A
k
B
1
22
26
ns
Low-to-High Level Output
or A
e
B
t
PHL
Propagation Delay Time
A
l
B
A
k
B
1
17
26
ns
High-to-Low Level Output
or A
e
B
3
Logic Diagram
TL F 6379 2
4
5