54FCT521 8-Bit Identity Comparator
September 1998
54FCT521
8-Bit Identity Comparator
General Description
The ’FCT521 is an expandable 8-bit comparator. It com-
pares 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
A = B
also serves as an active LOW enable input.
Features
n
Expandable to any word length
n
Outputs sink capability of 32mA, source capability of 12
mA
n
TTL input and output level compatible
n
CMOS power consumption
n
Standard microcircuit Drawing (SMD) 5962-8854301
Logic Symbols
Connection Diagram
Pin Assignment
for DIP and CERPACK
DS100968-1
IEEE/IEC
DS100968-2
Pin Assignment
for LCC
DS100968-4
DS100968-3
Pin Descriptions
Pin Names
A
0
–A
7
B
0
–B
7
T
A = B
O
A = B
Word A Inputs
Word B Inputs
Expansion or Enable Input
Identity Output
Description
FACT
™
is a trademark of Fairchild Semiconductor Corporation.
© 1998 National Semiconductor Corporation
DS100968
www.national.com
Absolute Maximum Ratings
(Note 2)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage (V
CC
)
DC Input Diode Current (I
IK
)
V
I
= −0.5V
V
I
= V
CC
+ 0.5V
DC Input Voltage (V
I
)
DC Output Diode Current (I
OK
)
V
O
= −0.5V
V
O
= V
CC
+ 0.5V
DC Output Voltage (V
O
)
DC Output Source
or Sink Current (I
O
)
DC V
CC
or Ground Current
per Output Pin (I
CC
or I
GND
)
−0.5V to +7.0V
−20 mA
+20 mA
−0.5V to V
CC
+ 0.5V
−20 mA
+20 mA
−0.5V to V
CC
+ 0.5V
Storage Temperature (T
STG
)
Junction Temperature (T
J
)
CDIP
−65˚C to +150˚C
175˚C
Recommended Operating
Conditions
Supply Voltage (V
CC
)
FCT
Input Voltage (V
I
)
Output Voltage (V
O
)
Operating Temperature (T
A
)
54FCT
4.5V to 5.5V
0V to V
CC
0V to V
CC
−55˚C to +125˚C
±
50 mA
±
50 mA
Note 2:
Absolute maximum ratings are those values beyond which damage
to the device may occur. The databook specifications should be met, without
exception, to ensure that the system design is reliable over its power supply,
temperature, output/input loading variables. National does not recommend
operation of FACT
™
circuits outside databook specifications.
DC Electrical Characteristics for ’FCT Family Devices
Symbol
V
IH
V
IL
V
CD
V
OH
V
OL
I
IH
I
IL
I
OS
I
CCQ
∆I
CC
I
CCD
Parameter
Min
Input HIGH Voltage
Input LOW Voltage
Input Clamp Diode Voltage
Output HIGH Voltage
Output LOW Voltage
Input HIGH Current
Input LOW Current
Output Short-Circuit Current
Quiescent Power
Supply Current
Quiescent Power
Supply Current
Dynamic I
CC
54FCT
54FCT
54FCT
54FCT
4.3
2.4
0.2
0.5
5
−5
-60
1.5
2.0
0.25
2.0
0.8
−1.2
54FCT
Max
V
V
V
V
V
V
V
µA
µA
mA
mA
mA
mA/
MHz
mA
Min
Min
Min
Min
Min
Max
Max
Max
Max
Max
Max
Recognized HIGH Signal
Recognized LOW Signal
I
IN
= −18 mA
I
OH
= −300 µA
I
OH
= −12 mA
I
OL
= 300 µA
I
OL
= 32 mA
V
IN
= V
CC
V
IN
= 0.0V
V
OUT
= 0.0V
V
IN
<
0.2V or V
IN
5.3V, V
CC
=
5.5V
V
I
= V
CC
− 2.1V
V
CC
= 5.5V, Outputs Open,
One Bit Toggling, 50% Duty
Cycle, OE
n
= GND
V
CC
= 5.5V, Outputs Open, fI
= 10MHz, OE
n
= GND, One
Bit Toggling, 50% Duty Cycle
Units
V
CC
Conditions
I
CC
Total Power Supply
Current
5.0
Max
Note 3:
All outputs loaded; thresholds on input associated with output under test.
Note 4:
Maximum test duration 2.0 ms, one output loaded at a time.
3
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AC Electrical Characteristics for ’FCT Family Devices
Symbol
Parameter
V
CC
(V)
(Note
5)
t
PLH
t
PHL
t
PLH
t
PHL
Propagation Delay
A
n
or B
n
to O
A
A
n
or B
n
to O
A
I
A
I
A
= B
= B
T
A
= −55˚C to +125˚C
C
L
= 50 pF
Min
1.5
1.5
1.5
1.5
Max
15.0
15.0
9.0
9.0
Units
5.0
5.0
5.0
5.0
ns
ns
ns
ns
Propagation Delay
= B
Propagation Delay
to O
A
to O
A
= B
Propagation Delay
= B
= B
Note 5:
Voltage Range 5.0 is 5.0V
±
0.5V
Capacitance
Symbol
C
IN
C
PD
Parameter
Input Capacitance
Power Dissipation Capacitance
Typ
4.5
40
Units
pF
pF
Conditions
V
CC
= OPEN
V
CC
= 5.0V
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