NSC DM74LS85M

54LS85/DM54LS85/DM74LS85
4-Bit Magnitude Comparators
General Description
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.
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 expandable to any number of bits without external gates. Words of
greater length may be compared by connecting comparators 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 corresponding inputs of the next stage handling more-significant bits. The stage handling the least-significant bits must
Features
Y
Y
Y
Typical power dissipation 52 mW
Typical delay (4-bit words) 24 ns
Alternate Military/Aerospace device (54LS85) is available. Contact a National Semiconductor Sales Office/
Distributor for specifications.
Connection Diagram
Dual-In-Line Package
Order Number 54LS85DMQB,
54LS85FMQB, 54LS85LMQB,
DM54LS85J, DM54LS85W,
DM74LS85M or DM74LS85N
See NS Package Number E20A,
J16A, M16A, N16E or W16A
TL/F/6379 – 1
Function Table
Comparing
Inputs
Cascading
Inputs
Outputs
A3, B3
A2, B2
A1, B1
A0, B0
AlB
AkB
AeB
AlB
AkB
AeB
A3 l B3
A3 k B3
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
H
L
L
X
H
L
X
X
X
X
X
X
X
X
L
H
L
X
H
L
X
X
X
X
X
X
X
X
L
L
H
H
L
L
H
L
H
L
H
L
H
L
H
L
L
L
L
H
L
H
L
H
L
H
L
H
L
H
L
L
L
H
L
L
L
L
L
L
L
L
L
L
H
H
L
L
A3
A3
A3
A3
A3
A3
A3
A3
A3
A3
A3
A3
e
e
e
e
e
e
e
e
e
e
e
e
B3
B3
B3
B3
B3
B3
B3
B3
B3
B3
B3
B3
A2 l B2
A2 k B2
A2 e B2
A2 e B2
A2 e B2
A2 e B2
A2 e B2
A2 e B2
A2 e B2
A2 e B2
A2 e B2
A2 e B2
A1 l B1
A1 k B1
A1 e B1
A1 e B1
A1 e B1
A1 e B1
A1 e B1
A1 e B1
A1 e B1
A1 e B1
A0 l B0
A0 k B0
A0 e B0
A0 e B0
A0 e B0
A0 e B0
A0 e B0
A0 e B0
H e High Level, L e Low Level, X e Don’t Care
C1995 National Semiconductor Corporation
TL/F/6379
RRD-B30M105/Printed in U. S. A.
54LS85/DM54LS85/DM74LS85 4-Bit Magnitude Comparators
June 1989
Absolute Maximum Ratings (Note)
Note: The ‘‘Absolute Maximum Ratings’’ are those values
beyond which the safety of the device cannot be guaranteed. 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.
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
b 55§ C to a 125§ C
DM54LS and 54LS
DM74LS
0§ C to a 70§ C
Storage Temperature Range
b 65§ C to a 150§ C
Recommended Operating Conditions
Symbol
DM54LS85
Parameter
VCC
Supply Voltage
VIH
High Level Input Voltage
VIL
Low Level Input Voltage
IOH
High Level Output Current
IOL
Low Level Output Current
TA
Free Air Operating Temperature
DM74LS85
Units
Min
Nom
Max
Min
Nom
Max
4.5
5
5.5
4.75
5
5.25
V
0.7
0.8
V
b 0.4
b 0.4
mA
8
mA
70
§C
2
2
V
4
b 55
125
0
Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted)
Symbol
VI
VOH
VOL
II
IIH
IIL
IOS
ICC
Parameter
Conditions
Min
Typ
(Note 1)
Max
Units
b 1.5
V
Input Clamp Voltage
VCC e Min, II e b18 mA
High Level Output
Voltage
VCC e Min, IOH e Max
VIL e Max, VIH e Min
DM54
2.5
3.4
DM74
2.7
3.4
Low Level Output
Voltage
VCC e Min, IOL e Max
VIL e Max, VIH e Min
DM54
0.25
0.4
DM74
0.35
0.5
IOL e 4 mA, VCC e Min
DM74
0.25
0.4
VCC e Max
VI e 7V
AkB
Input Current @ Max
Input Voltage
High Level Input
Current
Low Level Input
Current
VCC e Max
VI e 2.7V
VCC e Max
VI e 0.4V
Short Circuit
Output Current
VCC e Max
(Note 2)
Supply Current
VCC e Max (Note 3)
0.1
Others
0.3
AkB
20
AlB
20
Others
60
AkB
b 0.4
AlB
b 0.4
Others
b 1.2
DM54
b 20
b 100
DM74
b 20
b 100
10
Note 2: Not more than one output should be shorted at a time, and the duration should not exceed one second.
Note 3: ICC is measured with all outputs open, A e B grounded and all other inputs at 4.5V.
V
0.1
AlB
Note 1: All typicals are at VCC e 5V, TA e 25§ C.
2
V
20
mA
mA
mA
mA
mA
Switching Characteristics at VCC e 5V and TA e 25§ C (See Section 1 for Test Waveforms and Output Load)
Symbol
Parameter
From
Input
To
Output
Number of
Gate Levels
RL e 2 kX
CL e 15 pF
Min
tPLH
tPHL
Propagation Delay Time
Low-to-High Level Output
Propagation Delay Time
High-to-Low Level Output
Any A or B
Data Input
Any A or B
Data Input
Max
CL e 50 pF
Min
Units
Max
A k B,
AlB
3
36
42
AeB
4
40
40
A k B,
AlB
3
30
40
AeB
4
30
40
ns
ns
tPLH
Propagation Delay Time
Low-to-High Level Output
AkB
or A e B
AlB
1
22
26
ns
tPHL
Propagation Delay Time
High-to-Low Level Output
AkB
or A e B
AlB
1
17
26
ns
tPLH
Propagation Delay Time
Low-to-High Level Output
A eB
AeB
2
20
25
ns
tPHL
Propagation Delay Time
High-to-Low Level Output
AeB
AeB
2
17
26
ns
tPLH
Propagation Delay Time
Low-to-High Level Output
AlB
or A e B
AkB
1
22
26
ns
tPHL
Propagation Delay Time
High-to-Low Level Output
AlB
or A e B
AkB
1
17
26
ns
3
Logic Diagram
TL/F/6379 – 2
4
5
Physical Dimensions inches (millimeters)
Chip Carrier Package (E)
Order Number 54LS85LMQB
NS Package Number E20A
16-Lead Ceramic Dual-In-Line Package (J)
Order Number 54LS85DMQB or DM54LS85J
NS Package Number J16A
6
Physical Dimensions inches (millimeters) (Continued)
16-Lead Small Outline Molded Package (M)
Order Number DM74LS85M
NS Package Number M16A
16-Lead Molded Dual-In-Line Package (N)
Order Number DM74LS85N
NS Package Number N16E
7
54LS85/DM54LS85/DM74LS85 4-Bit Magnitude Comparators
Physical Dimensions inches (millimeters) (Continued)
16-Lead Ceramic Flat Package (W)
Order Number 54LS85FMQB or DM54LS85W
NS Package Number W16A
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