Magnitude Comparator. DM74LS85 Datasheet

DM74LS85 Comparator. Datasheet pdf. Equivalent

DM74LS85 Datasheet
Recommendation DM74LS85 Datasheet
Part DM74LS85
Description 4-Bit Magnitude Comparator
Feature DM74LS85; DM74LS85 4-Bit Magnitude Comparator August 1986 Revised March 2000 DM74LS85 4-Bit Magnitude Compar.
Manufacture Fairchild
Datasheet
Download DM74LS85 Datasheet





Fairchild DM74LS85
August 1986
Revised March 2000
DM74LS85
4-Bit Magnitude Comparator
General Description
These 4-bit magnitude comparators perform comparison of
straight binary or BCD codes. Three fully-decoded deci-
sions about two, 4-bit words (A, B) are made and are exter-
nally 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 > B, A < B, and A = B out-
puts 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 have a high-level voltage applied to
the A = B input. The cascading path is implemented with
only a two-gate-level delay to reduce overall comparison
times for long words.
Features
s Typical power dissipation 52 mW
s Typical delay (4-bit words) 24 ns
Ordering Code:
Order Number Package Number
Package Description
DM74LS85M
M16A
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
DM74LS85N
N16E
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Connection Diagram
© 2000 Fairchild Semiconductor Corporation DS006379
www.fairchildsemi.com



Fairchild DM74LS85
Function Table
Comparing
Inputs
A3, B3 A2, B2 A1, B1
A3 > B3
X
X
A3 < B3
X
X
A3 = B3 A2 > B2
X
A3 = B3 A2 < B2
X
A3 = B3 A2 = B2 A1 > B1
A3 = B3 A2 = B2 A1 < B1
A3 = B3 A2 = B2 A1 = B1
A3 = B3 A2 = B2 A1 = B1
A3 = B3 A2 = B2 A1 = B1
A3 = B3 A2 = B2 A1 = B1
A3 = B3 A2 = B2 A1 = B1
A3 = B3 A2 = B2 A1 = B1
A3 = B3 A2 = B2 A1 = B1
A3 = B3 A2 = B2 A1 = B1
H = HIGH Level, L = LOW Level, X = Don’t Care
A0, B0
X
X
X
X
X
X
A0 > B0
A0 < B0
A0 = B0
A0 = B0
A0 = B0
A0 = B0
A0 = B0
A0 = B0
Cascading
Inputs
A>B A<B A=B
XXX
XXX
XXX
XXX
XXX
XXX
XXX
XXX
HL L
LHL
L LH
XXH
HH L
LLL
Outputs
A>B
H
L
H
L
H
L
H
L
H
L
L
L
L
H
A<B
L
H
L
H
L
H
L
H
L
H
L
L
L
H
A=B
L
L
L
L
L
L
L
L
L
L
H
H
L
L
Logic Diagram
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2



Fairchild DM74LS85
Absolute Maximum Ratings(Note 1)
Supply Voltage
7V
Input Voltage
7V
Operating Free Air Temperature Range 0°C to +70°C
Storage Temperature Range
65°C to +150°C
Note 1: 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 tables 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
VCC
VIH
VIL
IOH
IOL
TA
Parameter
Supply Voltage
HIGH Level Input Voltage
LOW Level Input Voltage
HIGH Level Output Current
LOW Level Output Current
Free Air Operating Temperature
Min
4.75
2
Nom
5
0
Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted)
Symbol
Parameter
Conditions
Min
VI Input Clamp Voltage
VOH HIGH Level
Output Voltage
VOL LOW Level
Output Voltage
II Input Current @ Max
Input Voltage
VCC = Min, II = −18 mA
VCC = Min, IOH = Max
VIL = Max, VIH = Min
VCC = Min, IOL = Max
VIL = Max, VIH = Min
IOL = 4 mA, VCC = Min
VCC = Max
VI = 7V
2.7
A<B
A>B
Others
IIH HIGH Level
Input Current
VCC = Max
VI = 2.7V
A<B
A>B
Others
IIL LOW Level
Input Current
VCC = Max
VI = 0.4V
A<B
A>B
Others
IOS Short Circuit Output Current
ICC Supply Current
Note 2: All typicals are at VCC = 5V, TA = 25°C.
VCC = Max (Note 3)
VCC = Max (Note 4)
20
Note 3: Not more than one output should be shorted at a time, and the duration should not exceed one second.
Note 4: ICC is measured with all outputs OPEN, A = B grounded and all other inputs at 4.5V.
Max
Units
5.25
V
V
0.8 V
0.4
mA
8 mA
70 °C
Typ
(Note 2)
3.4
0.35
0.25
10
Max
1.5
0.5
0.4
0.1
0.1
0.3
20
20
60
0.4
0.4
1.2
100
20
Units
V
V
V
mA
µA
mA
mA
mA
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