NSC 54F521LMQB, 54F521DMQB, 54F521DM Datasheet
TL/F/9545
54F/74F521 8-Bit Identity Comparator
May 1995
54F/74F521
8-Bit Identity Comparator
General Description
The ’F521 is an expandable 8-bit comparator. It compares
two words of up to eight bits each and provides a LOW
output when the two words match bit for bit. The expansion
input I
AeB
also serves as an active LOW enable input.
Features
Y
Compares two 8-bit words in 6.5 ns typ
Y
Expandable to any word length
Y
20-pin package
Commercial Military
Package
Package Description
Number
74F521PC N20A 20-Lead (0.300×Wide) Molded Dual-In-Line
54F521DM (Note 2) J20A 20-Lead Ceramic Dual-In-Line
74F521SC (Note 1) M20B 20-Lead (0.300×Wide) Molded Small Outline, JEDEC
74F521SJ (Note 1) M20D 20-Lead (0.300×Wide) Molded Small Outline, EIAJ
74F521MSA (Note 1) MSA20 20-Lead Molded Shrink Small Outline, EIAJ type II
Note 1: Devices also available in 13×reel. Use suffixeSCX, SJX and MSAX.
Note 2: Military grade device with environmental and burn-in processing. Use suffix
e
DMQB.
Logic Symbols
TL/F/9545– 1
IEEE/IEC
TL/F/9545– 4
TRI-STATEÉis a registered trademark of National Semiconductor Corporation.
C
1995 National Semiconductor Corporation RRD-B30M75/Printed in U. S. A.
Unit Loading/Fan Out
54F/74F
Pin Names Description
U.L. Input I
IH/IIL
HIGH/LOW Output IOH/I
OL
A0–A
7
Word A Inputs 1.0/1.0 20 mA/b0.6 mA
B
0–B7
Word B Inputs 1.0/1.0 20 mA/b0.6 mA
I
AeB
Expansion or Enable Input (Active LOW) 1.0/1.0 20 mA/b0.6 mA
O
AeB
Identity Output (Active LOW) 50/33.3
b
1 mA/20 mA
Truth Table
Inputs Output
I
AeB
A, B O
AeB
LA
e
B* L
LA
i
BH
HA
e
B* H
HA
i
BH
H
e
HIGH Voltage Level
L
e
LOW Voltage Level
*A
0
e
B0,A
1
e
B1,A
2
e
B2, etc.
Connection Diagrams
Pin Assignment for DIP,
SOIC, SSOP and Flatpak
TL/F/9545– 2
Pin Assignment
for LCC
TL/F/9545– 3
Logic Diagram
TL/F/9545– 5
Please note that this diagram is provided only for the understanding of logic operations and should not be
used to estimate propagation delays.
2
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.
Storage Temperature
b
65§Ctoa150§C
Ambient Temperature under Bias
b
55§Ctoa125§C
Junction Temperature under Bias
b
55§Ctoa175§C
Plastic
b
55§Ctoa150§C
V
CC
Pin Potential to
Ground Pin
b
0.5V toa7.0V
Input Voltage (Note 2)
b
0.5V toa7.0V
Input Current (Note 2)
b
30 mA toa5.0 mA
Voltage Applied to Output
in HIGH State (with V
CC
e
0V)
Standard Output
b
0.5V to V
CC
TRI-STATEÉOutput
b
0.5V toa5.5V
Current Applied to Output
in LOW State (Max) twice the rated I
OL
(mA)
Note 1: Absolute maximum ratings are values beyond which the device may
be damaged or have its useful life impaired. Functional operation under
these conditions is not implied.
Note 2: Either voltage limit or current limit is sufficient to protect inputs.
Recommended Operating
Conditions
Free Air Ambient Temperature
Military
b
55§Ctoa125§C
Commercial 0
§
Ctoa70§C
Supply Voltage
Military
a
4.5V toa5.5V
Commercial
a
4.5V toa5.5V
DC Electrical Characteristics
Symbol Parameter
54F/74F
Units V
CC
Conditions
Min Typ Max
V
IH
Input HIGH Voltage 2.0 V Recognized as a HIGH Signal
V
IL
Input LOW Voltage 0.8 V Recognized as a LOW Signal
V
CD
Input Clamp Diode Voltage
b
1.2 V Min I
IN
eb
18 mA
V
OH
Output HIGH 54F 10% V
CC
2.5 I
OH
eb
1mA
Voltage 74F 10% V
CC
2.5 V Min I
OH
eb
1mA
74F 5% V
CC
2.7 I
OH
eb
1mA
V
OL
Output LOW 54F 10% V
CC
0.5
V Min
I
OL
e
20 mA
Voltage 74F 10% V
CC
0.5 I
OL
e
20 mA
I
IH
Input HIGH 54F 20.0
mA Max V
IN
e
2.7V
Current 74F 5.0
I
BVI
Input HIGH Current 54F 100
mA Max V
IN
e
7.0V
Breakdown Test 74F 7.0
I
CEX
Output HIGH 54F 250
mA Max V
OUT
e
V
CC
Leakage Current 74F 50
V
ID
Input Leakage
74F 4.75 V 0.0
I
ID
e
1.9 mA
Test All Other Pins Grounded
I
OD
Output Leakage
74F 3.75 mA 0.0
V
IOD
e
150 mV
Circuit Current All Other Pins Grounded
I
IL
Input LOW Current
b
0.6 mA Max V
IN
e
0.5V
I
OS
Output Short-Circuit Current
b
60
b
150 mA Max V
OUT
e
0V
I
CCH
Power Supply Current 21 32 mA Max V
O
e
HIGH
3
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