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54LS85DM

Part # 54LS85DM
Description MAGNITUDE COMPARATOR, TTL
Category IC
Availability In Stock
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Fairchild Semiconductor
Date Code: 8002
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Technical Document


DISCLAIMER: The information provided herein is solely for informational purposes. Customers must be aware of the suitability of this product for their application, and consider that variable factors such as Manufacturer, Product Category, Date Codes, Pictures and Descriptions may differ from available inventory.

TL/F/6379
54LS85/DM54LS85/DM74LS85 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/63791
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
BA
k
BA
e
BA
l
BA
k
BA
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
B0LLHLLH
A3
e
B3 A2
e
B2 A1
e
B1 A0
e
B0XXHLLH
A3
e
B3 A2
e
B2 A1
e
B1 A0
e
B0HHLLLL
A3
e
B3 A2
e
B2 A1
e
B1 A0
e
B0LLLHHL
H
e
High Level, L
e
Low Level, X
e
Don’t Care
C
1995 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
§
Cto
a
125
§
C
DM74LS 0
§
Cto
a
70
§
C
Storage Temperature Range
b
65
§
Cto
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
eb
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
B20
Current V
I
e
2.7V
A
l
B20mA
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
2kX
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,
33642
Low-to-High Level Output Data Input A
l
Bns
A
e
B 4 40 40
t
PHL
Propagation Delay Time Any A or B A
k
B,
33040
High-to-Low Level Output Data Input A
l
Bns
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
BA
e
B 2 20 25 ns
Low-to-High Level Output
t
PHL
Propagation Delay Time
A
e
BA
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
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