DM74ALS520 • DM74ALS521 8-Bit Comparator
September 1986
Revised April 2000
DM74ALS520 • DM74ALS521
8-Bit Comparator
General Description
These comparators perform an “equal to” comparison of
two 8-bit words with provision for expansion or external
enabling. The matching of the two 8-bit input plus a logic
LOW on the EN input produces the output A
=
B on the
DM74ALS520 and DM74ALS521. The DM74ALS520 and
DM74ALS521 have totem pole outputs for wire AND cas-
cading. Additionally, the DM74ALS520 is provided with B
input pull up termination resistors for analog or switch data.
Features
s
Switching specifications at 50 pF
s
Switching specifications guaranteed over full tempera-
ture and V
CC
range
s
Advanced oxide-isolated, ion-implanted Schottky TTL
process
s
Functionally and pin for pin compatible with LS family
counterpart
s
Improved output transient handling capability
Ordering Code:
Ordering Code
DM74ALS520WM
DM74ALS520N
DM74ALS521WM
SM74ALS521N
Package Number
M20B
N20A
M20B
N20A
Package Description
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
20-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
Function Table
Inputs
EN
L
L
H
H
=
HIGH Logic Level
L
=
LOW Logic Level
X
=
Don't Care
Output
Data
A
=
B
A
≠
B
X
A
=
B
L
H
H
© 2000 Fairchild Semiconductor Corporation
DS006114
www.fairchildsemi.com
DM74ALS520 • DM74ALS521
Logic Diagram
www.fairchildsemi.com
2
DM74ALS520 • DM74ALS521
Absolute Maximum Ratings
(Note 1)
Supply Voltage
Input Voltage
Operating Free Air Temperature Range
Storage Temperature Range
Typical
θ
JA
N Package
M Package
62.0°C/W
82.0°C/W
7V
7V
0°C to
+70°C
−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
V
CC
V
IH
V
IL
I
OH
I
OL
T
A
Supply Voltage
HIGH Level Input Voltage
LOW Level Input Voltage
HIGH Level Output Current
LOW Level Output Current
Free Air Operating Temperature
0
Parameter
Min
4.5
2
0.8
−2.6
24
70
Nom
5
Max
5.5
Units
V
V
V
mA
mA
°C
Electrical Characteristics
over recommended operating free air temperature range. All typical values are measured at V
CC
=
5V, T
A
=
25°C.
Symbol
V
IK
V
OH
Parameter
Input Clamp Voltage
HIGH Level
Output Voltage
V
CC
=
4.5V to 5.5V
I
OH
= −400 µA
V
CC
=
4.5V
I
OH
=
Max
V
OL
I
I
LOW Level Output Voltage
Max HIGH
Input Current
I
IH
I
IL
I
O
I
CC
HIGH Level
Input Current
Low Level Input
Current
Output Drive Current
Supply Current
V
CC
=
5.5V,
V
IH
=
2.7V
V
CC
=
5.5V,
V
IL
=
0.4V
V
CC
=
5.5V
V
CC
=
5.5V (Note 2)
V
CC
=
4.5V
V
CC
=
5.5V
I
OL
=
24 mA
V
IH
=
5.5V
B Input DM74ALS520
V
IH
=
7V, All Others
All Others
B Input DM74ALS520
B Input DM74ALS520
All Others
V
O
=
2.25V
−30
12
20
−200
−0.6
−0.1
−112
19
µA
mA
mA
mA
mA
0.1
mA
Conditions
V
CC
=
4.5V, I
I
= −18
mA
V
CC
−
2
2.4
3.2
0.35
0.5
Min
Typ
Max
−1.5
Units
V
V
V
V
Note 2:
I
CC
is measured with EN grounded, A and B inputs at 4.5V and outputs OPEN.
Switching Characteristics
over recommended operating free air temperature range
Symbol
t
PLH
Parameter
Propagation Delay Time
LOW-to-HIGH Level Output
t
PHL
Propagation Delay Time
HIGH-to-LOW Level Output
t
PLH
Propagation Delay Time
LOW-to-HIGH Level Output
t
PHL
Propagation Delay Time
HIGH-to-LOW Level Output
Conditions
V
CC
=
4.5V to 5.5V
C
L
=
50 pF
R
L
=
500Ω
From
Input
A or B
Data
A or B
Data
EN
To
Output
A
=
B
A
=
B
A
=
B
A
=
B
Min
Max
Units
3
12
ns
5
20
ns
2
12
ns
EN
5
22
ns
3
www.fairchildsemi.com
DM74ALS520 • DM74ALS521
Physical Dimensions
inches (millimeters) unless otherwise noted
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
Package Number M20B
www.fairchildsemi.com
4
DM74ALS520 • DM74ALS521 8-Bit Comparator
Physical Dimensions
inches (millimeters) unless otherwise noted (Continued)
20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Package Number N20A
Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and
Fairchild reserves the right at any time without notice to change said circuitry and specifications.
LIFE SUPPORT POLICY
FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD
SEMICONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the
body, or (b) support or sustain life, and (c) whose failure
to perform when properly used in accordance with
instructions for use provided in the labeling, can be rea-
sonably expected to result in a significant injury to the
user.
5
2. A critical component in any component of a life support
device or system whose failure to perform can be rea-
sonably expected to cause the failure of the life support
device or system, or to affect its safety or effectiveness.
www.fairchildsemi.com
www.fairchildsemi.com
京公网安备 11010802033920号
EEWORLD
