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 Descriptions
Pin Names
Description
A
0
A
7
Word A Inputs
B
0
B
7
Word B Inputs
T
A = B
Expansion or Enable Input
O
A = B
Identity Output
FACT
TM
is a trademark of Fairchild Semiconductor Corporation.
DS100968-1
IEEE/IEC
DS100968-4
Pin Assignment
for DIP and CERPACK
DS100968-2
Pin Assignment
for LCC
DS100968-3
September 1998
54FCT521
8-Bit
Identity
Comparator
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
)
-0.5V to +7.0V
DC Input Diode Current (I
IK
)
V
I
= -0.5V
-20 mA
V
I
= V
CC
+ 0.5V
+20 mA
DC Input Voltage (V
I
)
-0.5V to V
CC
+ 0.5V
DC Output Diode Current (I
OK
)
V
O
= -0.5V
-20 mA
V
O
= V
CC
+ 0.5V
+20 mA
DC Output Voltage (V
O
)
-0.5V to V
CC
+ 0.5V
DC Output Source
or Sink Current (I
O
)
50 mA
DC V
CC
or Ground Current
per Output Pin (I
CC
or I
GND
)
50 mA
Storage Temperature (T
STG
)
-65C to +150C
Junction Temperature (T
J
)
CDIP
175C
Recommended Operating
Conditions
Supply Voltage (V
CC
)
FCT
4.5V to 5.5V
Input Voltage (V
I
)
0V to V
CC
Output Voltage (V
O
)
0V to V
CC
Operating Temperature (T
A
)
54FCT
-55C to +125C
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
TM
circuits outside databook specifications.
DC Electrical Characteristics for 'FCT Family Devices
Symbol
Parameter
54FCT
Units
V
CC
Conditions
Min
Max
V
IH
Input HIGH Voltage
2.0
V
Recognized HIGH Signal
V
IL
Input LOW Voltage
0.8
V
Recognized LOW Signal
V
CD
Input Clamp Diode Voltage
-1.2
V
Min
I
IN
= -18 mA
V
OH
Output HIGH Voltage
54FCT
4.3
V
Min
I
OH
= -300 A
54FCT
2.4
V
Min
I
OH
= -12 mA
V
OL
Output LOW Voltage
54FCT
0.2
V
Min
I
OL
= 300 A
54FCT
0.5
V
Min
I
OL
= 32 mA
I
IH
Input HIGH Current
5
A
Max
V
IN
= V
CC
I
IL
Input LOW Current
-5
A
Max
V
IN
= 0.0V
I
OS
Output Short-Circuit Current
-60
mA
Max
V
OUT
= 0.0V
I
CCQ
Quiescent Power
Supply Current
1.5
mA
Max
V
IN
<
0.2V or V
IN
5.3V, V
CC
=
5.5V
I
CC
Quiescent Power
Supply Current
2.0
mA
Max
V
I
= V
CC
- 2.1V
I
CCD
Dynamic I
CC
0.25
mA/
MHz
Max
V
CC
= 5.5V, Outputs Open,
One Bit Toggling, 50% Duty
Cycle, OE
n
= GND
I
CC
Total Power Supply
Current
5.0
mA
Max
V
CC
= 5.5V, Outputs Open, fI
= 10MHz, OE
n
= GND, One
Bit Toggling, 50% Duty Cycle
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.
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3
AC Electrical Characteristics for 'FCT Family Devices
Symbol
Parameter
V
CC
T
A
= -55C to +125C
Units
(V)
C
L
= 50 pF
(Note
5)
Min
Max
t
PLH
Propagation Delay
5.0
1.5
15.0
ns
A
n
or B
n
to O
A = B
t
PHL
Propagation Delay
5.0
1.5
15.0
ns
A
n
or B
n
to O
A = B
t
PLH
Propagation Delay
5.0
1.5
9.0
ns
I
A = B
to O
A = B
t
PHL
Propagation Delay
5.0
1.5
9.0
ns
I
A = B
to O
A = B
Note 5: Voltage Range 5.0 is 5.0V
0.5V
Capacitance
Symbol
Parameter
Typ
Units
Conditions
C
IN
Input Capacitance
4.5
pF
V
CC
= OPEN
C
PD
Power Dissipation Capacitance
40
pF
V
CC
= 5.0V
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