54AC251
54ACT251
8-Input Multiplexer with TRI-STATE
Output
General Description
The 'AC/'ACT251 is a high-speed 8-input digital multiplexer.
It provides, in one package, the ability to select one bit of
data from up to eight sources. It can be used as universal
function generator to generate any logic function of four vari-
ables. Both true and complementary outputs are provided.
Features
n
I
CC
reduced by 50%
n
Multifunctional capability
n
On-chip select logic decoding
n
Inverting and noninverting TRI-STATE outputs
n
Outputs source/sink 24 mA
n
'ACT251 has TTL-compatible inputs
n
Standard Military Drawing (SMD)
-- 'AC251: 5962-87692
-- 'ACT251: 5962-89599
Logic Symbols
Pin Names
Description
S
0
S
2
Select Inputs
OE
TRI-STATE Output Enable Input
I
0
I
7
Multiplexer Inputs
Z
TRI-STATE Multiplexer Output
Z
Complementary TRI-STATE Multiplexer
Output
TRI-STATE
is a registered trademark of National Semiconductor Corporation.
FACT
is a registered trademark of Fairchild Semiconductor Corporation.
DS100284-1
IEEE/IEC
DS100284-2
August 1998
54AC251
54ACT251
8-Input
Multiplexer
with
TRI-ST
A
T
E
Output
1998 National Semiconductor Corporation
DS100284
www.national.com
Connection Diagrams
Functional Description
This device is a logical implementation of a single-pole,
8-position switch with the switch position controlled by the
state of three Select inputs, S
0
, S
1
, S
2
. Both true and
complementary outputs are provided. The Output Enable in-
put ( OE) is active LOW. When it is activated, the logic func-
tion provided at the output is:
Z = OE
(I
0
S
0
S
1
S
2
+ I
1
S
0
S
1
S
2
+
I
2
S
0
S
1
S
2
+ I
3
S
0
S
1
S
2
+
I
4
S
0
S
1
S
2
+ I
5
S
0
S
1
S
2
+
I
6
S
0
S
1
S
2
+ I
7
S
0
S
1
S
2
)
When the Output Enable is HIGH, both outputs are in the
high impedance (High Z) state. This feature allows multi-
plexer expansion by tying the outputs of up to 128 devices
together. When the outputs of the TRI-STATE devices are
tied together, all but one device must be in the high imped-
ance state to avoid high currents that would exceed the
maximum ratings. The Output Enable signals should be de-
signed to ensure there is no overlap in the active-LOW por-
tion of the enable voltages.
Truth Table
Inputs
Outputs
OE
S
2
S
1
S
0
Z
Z
H
X
X
X
Z
Z
L
L
L
L
I
0
I
0
L
L
L
H
I
1
I
1
L
L
H
L
I
2
I
2
L
L
H
H
I
3
I
3
L
H
L
L
I
4
I
4
L
H
L
H
I
5
I
5
L
H
H
L
I
6
I
6
L
H
H
H
I
7
I
7
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
Z = High Impedance
Pin Assignment
for DIP and Flatpak
DS100284-3
Pin Assignment
for LCC
DS100284-4
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2
Logic Diagram
DS100284-5
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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3
Absolute Maximum Ratings
(Note 1)
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
)
'AC
2.0V to 6.0V
'ACT
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
)
54AC/ACT
-55C to +125C
Minimum Input Edge Rate (
V/
t)
'AC Devices
V
IN
from 30% to 70% of V
CC
V
CC
@
3.3V, 4.5V, 5.5V
125 mV/ns
Minimum Input Edge Rate (
V/
t)
'ACT Devices
V
IN
from 0.8V to 2.0V
V
CC
@
4.5V, 5.5V
125 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.
Note 2: All outputs loaded; thresholds on input associated with output under
test.
DC Characteristics for 'AC Family Devices
54AC
Symbol
Parameter
V
CC
T
A
= -55C to +125C
Units
Conditions
(V)
Guaranteed Limits
V
IH
Minimum High Level
3.0
2.1
V
OUT
= 0.1V
Input Voltage
4.5
3.15
V
or V
CC
- 0.1V
5.5
3.85
V
IL
Maximum Low Level
3.0
0.9
V
OUT
= 0.1V
Input Voltage
4.5
1.35
V
or V
CC
- 0.1V
5.5
1.65
V
OH
Minimum High Level
3.0
2.9
I
OUT
= -50 A
Output Voltage
4.5
4.4
V
5.5
5.4
(Note 2)
V
IN
= V
IL
or V
IH
3.0
2.4
I
OH
= -12 mA
4.5
3.7
V
I
OH
= -24 mA
5.5
4.7
I
OH
= -24 mA
V
OL
Maximum Low Level
3.0
0.1
I
OUT
= 50 A
Output Voltage
4.5
0.1
V
5.5
0.1
(Note 2)
V
IN
= V
IL
or V
IH
3.0
0.50
I
OL
= 12 mA
4.5
0.50
V
I
OL
= 24 mA
5.5
0.50
I
OL
= 24 mA
I
IN
Maximum Input
5.5
1.0
A
V
I
= V
CC
, GND
Leakage Current
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4
DC Characteristics for 'AC Family Devices
(Continued)
54AC
Symbol
Parameter
V
CC
T
A
= -55C to +125C
Units
Conditions
(V)
Guaranteed Limits
I
OZ
Maximum TRI-STATE
V
I
(OE) = V
IL
, V
IH
Current
5.5
5.0
A
V
I
= V
CC
, V
GND
V
O
= V
CC
, GND
I
OLD
Minimum Dynamic
5.5
50
mA
V
OLD
= 1.65V Max
I
OHD
Output Current (Note 3)
5.5
-50
mA
V
OHD
= 3.85V Min
I
CC
Maximum Quiescent
5.5
80.0
A
V
IN
= V
CC
or GND
Supply Current
Note 3: Maximum test duration 2.0 ms, one output loaded at a time.
Note 4: I
IN
and I
CC
@
3.0V are guaranteed to be less than or equal to the respective limit
@
5.5V V
CC
.
I
CC
for 54AC
@
25C is identical to 74AC
@
25C.
DC Characteristics for 'ACT Family Devices
54ACT
Symbol
Parameter
V
CC
T
A
= -55C to +125C
Units
Conditions
(V)
Guaranteed Limits
V
IH
Minimum High Level
4.5
2.0
V
V
OUT
= 0.1V
Input Voltage
5.5
2.0
or V
CC
- 0.1V
V
IL
Maximum Low Level
4.5
0.8
V
V
OUT
= 0.1V
Input Voltage
5.5
0.8
or V
CC
- 0.1V
V
OH
Minimum High Level
4.5
4.4
V
I
OUT
= -50 A
Output Voltage
5.5
5.4
(Note 5)
V
IN
= V
IL
or V
IH
4.5
3.70
V
I
OH
= -24 mA
5.5
4.70
I
OH
= -24 mA
V
OL
Maximum Low Level
4.5
0.1
V
I
OUT
= 50 A
Output Voltage
5.5
0.1
(Note 5)
V
IN
= V
IL
or V
IH
4.5
0.50
V
I
OL
= 24 mA
5.5
0.50
I
OL
= 24 mA
I
IN
Maximum Input
5.5
1.0
A
V
I
= V
CC
, GND
Leakage Current
I
OZ
Maximum TRI-STATE
5.5
5.0
A
V
I
= V
IL
, V
IH
Current
V
O
= V
CC
, GND
I
CCT
Maximum I
CC
/Input
5.5
1.6
mA
V
I
= V
CC
- 2.1V
I
OLD
Minimum Dynamic
5.5
50
mA
V
OLD
= 1.65V Max
I
OHD
Output Current (Note 6)
5.5
-50
mA
V
OHD
= 3.85V Min
I
CC
Maximum Quiescent
5.5
80.0
A
V
IN
= V
CC
Supply Current
or GND
Note 5: All outputs loaded; thresholds on input associated with output under test.
Note 6: Maximum test duration 2.0 ms, one output loaded at a time.
Note 7: I
CC
for 54ACT
@
25C is identical to 74ACT
@
25C.
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5
AC Electrical Characteristics
54AC
V
CC
T
A
= -55C
Symbol
Parameter
(V)
to +125C
Units
(Note 8)
C
L
= 50 pF
Min
Max
t
PLH
Propagation Delay
3.3
1.0
21.0
ns
S
n
to Z or Z
5.0
1.0
15.5
t
PHL
Propagation Delay
3.3
1.0
21.0
ns
S
n
to Z or Z
5.0
1.0
15.5
t
PLH
Propagation Delay
3.3
1.0
17.0
ns
I
n
to Z or Z
5.0
1.0
12.0
t
PHL
Propagation Delay
3.3
1.0
16.5
ns
I
n
to Z or Z
5.0
1.0
12.0
t
PZH
Output Enable Time
3.3
1.0
13.0
ns
OE to Z or Z
5.0
1.0
10.0
t
PZL
Output Enable Time
3.3
1.0
13.0
ns
OE to Z or Z
5.0
1.0
10.0
t
PHZ
Output Disable Time
3.3
3.5
14.0
ns
OE to Z or Z
5.0
2.5
11.0
t
PLZ
Output Disable Time
3.3
4.0
13.0
ns
OE to Z or Z
5.0
3.0
10.0
Note 8: Voltage Range 3.3 is 3.3V
0.3V
Voltage Range 5.0 is 5.0V
0.5V
AC Electrical Characteristics
54ACT
V
CC
T
A
= -55C
Symbol
Parameter
(V)
to +125C
Units
(Note 9)
C
L
= 50 pF
Min
Max
t
PLH
Propagation Delay
5.0
1.0
18.0
ns
S
n
to Z or Z
t
PHL
Propagation Delay
5.0
1.0
18.0
ns
S
n
to Z or Z
t
PLH
Propagation Delay
5.0
1.0
13.5
ns
I
n
to Z or Z
t
PHL
Propagation Delay
5.0
1.0
13.5
ns
I
n
to Z or Z
t
PZH
Output Enable Time
5.0
1.0
10.0
ns
OE to Z or Z
t
PZL
Output Enable Time
5.0
1.0
9.5
ns
OE to Z or Z
t
PHZ
Output Disable Time
5.0
1.0
12.5
ns
OE to Z or Z
t
PLZ
Output Disable Time
5.0
1.0
8.5
ns
OE to Z or Z
Note 9: Voltage Range 5.0 is 5.0V
0.5V
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6
Capacitance
Symbol
Parameter
Typ
Units
Conditions
C
IN
Input Capacitance
4.5
pF
V
CC
= OPEN
C
PD
Power Dissipation
70.0
pF
V
CC
= 5.0V
Capacitance
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7
8
Physical Dimensions
inches (millimeters) unless otherwise noted
20 Terminal Ceramic Leadless Chip Carrier (L)
NS Package Number E20A
16 Lead Ceramic Dual-In-Line Package (D)
NS Package Number J16A
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9
Physical Dimensions
inches (millimeters) unless otherwise noted (Continued)
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VICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMI-
CONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or sys-
tems which, (a) are intended for surgical implant into
the body, or (b) support or sustain life, and whose fail-
ure to perform when properly used in accordance
with instructions for use provided in the labeling, can
be reasonably expected to result in a significant injury
to the user.
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.
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Tel: 1-800-272-9959
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16 Lead Ceramic Flatpak (F)
NS Package Number W16A
54AC251
54ACT251
8-Input
Multiplexer
with
TRI-ST
A
T
E
Output
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.
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