54FCT138.pdf
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Pobierz
October 1999
54FCT138
1-of-8 Decoder/Demultiplexer
General Description
The FCT138 is a high-speed 1-of-8 decoder/demultiplexer.
This device is ideally suited for high-speed bipolar memory
chip select address decoding. The multiple input enables al-
low parallel expansion to a 1-of-24 decoder using just three
FCT138 devices or a 1-of-32 decoder using four FCT138 de-
vices and one inverter.
Features
n
Demultiplexing capability
n
Multiple input enable for easy expansion
n
Active LOW mutually exclusive outputs
n
Outputs sink capability of 32mA, source capability of
12mA
n
TTL input and output level compatible
n
CMOS power consumption
n
Standard Microcircuit Drawing (SMD) 5962-8765401
Ordering Code
Military
Package
Package Description
Number
54FCT138DMQB
J16A
16-Lead Ceramic Dual-In-Line
54FCT138FMQB
W16A
16-Lead Cerpack
54FCT138LMQB
E20A
20-Lead Ceramic Leadless Chip Carrier, Type C
Logic Symbols
Connection Diagrams
Pin Assignment
for DIP and Flatpak
DS100963-1
IEEE/IEC
DS100963-2
Pin Assignment
for LCC
DS100963-7
Pin Names
Description
A
0
–A
2
Address Inputs
E
1
–E
2
Enable Inputs
DS100963-3
E
3
Enable Input
O
0
–O
7
Outputs
FACT
®
is a registered trademark of Fairchild Semiconductor Corporation.
© 1999 National Semiconductor Corporation
DS100963
www.national.com
Functional Description
The FCT138 high-speed 1-of-8 decoder/demultiplexer ac-
cepts three binary weighted inputs (A
0
,A
1
,A
2
) and, when
enabled, provides eight mutually exclusive active-LOW out-
puts (O
0
–O
7
). The FCT138 features three Enable inputs,
two active-LOW (E
1
,E
2
) and one active-HIGH (E
3
). All out-
puts will be HIGH unless E
1
and E
2
are LOW and E
3
is
HIGH. This multiple enable function allows easy parallel ex-
pansion of the device to a 1-of-32 (5 lines to 32 lines) de-
coder with just four FCT138 devices and one inverter (see
Figure 1). The FCT138 can be used as an 8-output demulti-
plexer by using one of the active LOW Enable inputs as the
data input and the other Enable inputs as strobes. The En-
able inputs which are not used must be permanently tied to
their appropriate active-HIGH or active-LOW state.
Inputs
O
utpu
ts
E
1
E
2
E
3
A
0
A
1
A
2
O
0
O
1
O
2
O
3
O
4
O
5
O
6
O
7
HXXXXXHHHHHHHH
XHXXXXHHHHHHHH
XX L
XXXHHHHHHHH
L
L
HL
L
L
L
HHHHHHH
L
L
HHL
L
HL
HHHHHH
L
L
HL
HL
HHL
HHHHH
L
L
HHHL
HHHL
HHHH
L L HL L HHHHHL HHH
L L HHL HHHHHHL HH
L L HL HHHHHHHHL H
L L HHHHHHHHHHHL
H
=
HIGH Voltage Level
L
=
LOW Voltage Level
X
=
Immaterial
Logic Diagram
DS100963-4
Please note that this diagram is provided only for the understanding of logic operations and should not be used to estimate propagation delays.
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2
DS100963-5
FIGURE 1. Expansion to 1-of-32 Decoding
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
in LOW State (Max)
Twice the rated I
OL
(mA)
DC Latchup Source Current
−500 mA
Recommended Operating
Conditions
Free Air Ambient Temperature
Military
−65˚C to +150˚C
Ambient Temperature under Bias
−55˚C to +125˚C
Junction Temperature under Bias
Ceramic
−55˚C to +125˚C
−55˚C to +175˚C
Supply Voltage
Military
V
CC
Pin Potential to
Ground Pin
+4.5V to +5.5V
−0.5V to +7.0V
Minimum Input Edge Rate
t)
Data Input 50 mV/ns
Enable Input 20 mV/ns
Note 1:
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, and output/input loading variables. National does not recom-
mend operation of FACT
®
circuits outside databook specifications.
(
D
V/
D
Input Voltage (Note 1)
−0.5V to +7.0V
Input Current (Note 1)
−30 mA to +5.0 mA
Voltage Applied to Any Output
in the Disabled or
Power-Off State
−0.5V to +5.5V
in the HIGH State
−0.5V to V
CC
Current Applied to Output
DC Characteristics for ’FCT Family Devices
Symbol
Parameter
FCT138
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
I
IN
=
−18 mA
V
CD
Input Clamp Diode Voltage
−1.2
V
Min
I
OH
=
−300 µA
V
OH
Output HIGH
Voltage
54FCT
4.3
V
Min
I
OH
=
−12 mA
54FCT
2.4
I
OL
=
300 µA
V
OL
Output LOW
Voltage
54FCT
0.2
V
Min
I
OL
=
32 mA
54FCT
0.5
V
IN
=
V
CC
I
IH
Input HIGH Current
5
µA
Max
V
IN
=
0.0V
I
IL
Input LOW Current
−5
µA
Max
V
OUT
=
0.0V
I
OS
Output Short-Circuit Current
-60
mA
Max
V
IN
<
0.2V or V
IN
5.3V, V
CC
=
5.5V
I
CCQ
Quiescent Power Supply Current
1.5
mA
Max
V
I
=
3.4V, V
CC
= 5.5V
D
I
CC
Quiescent Power
Supply Current
2.0
mA
Max
I
CCD
Dynamic I
CC
0.4
mA/
MHz
Max
Outputs Open, V
CC
= 5.5V, V
IN
5.3V or V
IN
<
0.2V, One Bi
t
Toggling, 50% Duty Cycle, OE
=
GND, LE
=
V
CC
I
CCT
Total Power Supply
Current
5.5
mA
Max
Outputs Open, f
CP
= 10 MHz,
V
CC
= 5.5V, V
IN
5.3V or V
IN
<
0.2V, One B
it T
oggling, 50%
Duty Cycle, OE
=
GND, LE
=
V
CC
Note 2:
All outputs loaded; thresholds on input associated with output under test.
Note 3:
Maximum test duration 2.0 ms, one output loaded at a time.
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AC Electrical Characteristics
54FCT
T
A
=
−55˚C
V
CC
Fig.
Symbol
Parameter
(V)
to +125˚C
Units
No.
C
L
=
50 pF
(Note 4)
Min
Max
t
PLH
Propa
ga
tion Delay
5.0
1.0
12.0
ns
A
n
to O
n
t
PHL
Propa
ga
tion Delay
5.0
1.0
12.0
ns
A
n
to O
n
t
PLH
Propagation Delay
5.0
1.0
12.5
ns
E
1
or E
2
to O
n
t
PHL
Propagation Delay
5.0
1.0
12.5
ns
E
1
or E
2
to O
n
t
PLH
Propa
ga
tion Delay
5.0
1.0
12.5
ns
E
3
toOn
t
PHL
Propa
ga
tion Delay
5.0
1.0
12.5
ns
E
3
toOn
Note 4:
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
60.0
pF
V
CC
= 5.0V
Capacitance
5
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