Philips
Semiconductors
74ALS251
8input multiplexer (3State)
Product specification
IC05 Data Handbook
1991 Feb 08
INTEGRATED CIRCUITS
Philips Semiconductors
Product specification
74ALS251
8-input multiplexer (3-State)
2
1991 Feb 08
8531377 01670
FEATURES
8-to-1 multiplexing
On chip decoding
Multifunction capability
Inverting and non-inverting outputs
Both outputs are 3-State for further multiplexer expansion
DESCRIPTION
The 74ALS251 is a logic implementation of a single 8-position
switch with the switch position controlled by the state of three select
(S0, S1, S2) inputs. True (Y) and complementary (Y) outputs are
both provided.
The output enable (OE) is active Low. When OE is High, both
outputs are in High impedance state, allowing multiple connections
to a common bus without driving nor loading the bus significantly.
When the outputs of more than one device are tied together, the
user must ensure that there is no overlap in the active-Low portion
of the output enable voltages in order to avoid high currents that
could exceed the maximum current rating.
TYPE
TYPICAL
PROPAGATION DELAY
TYPICAL
SUPPLY CURRENT
(TOTAL)
74ALS251
7.0ns
7.5mA
PIN CONFIGURATION
16
15
14
13
12
11
10
7
6
5
4
3
2
1
OE
V
CC
I7
S0
S1
I6
I4
I5
I3
I2
Y
I1
I0
Y
9
8
GND
S2
SC00066
ORDERING INFORMATION
ORDER CODE
DESCRIPTION
COMMERCIAL RANGE
V
CC
= 5V
10%,
T
amb
= 0
C to +70
C
DRAWING
NUMBER
16-pin plastic DIP
74ALS251N
SOT38-4
16-pin plastic SO
74ALS251D
SOT109-1
INPUT AND OUTPUT LOADING AND FAN-OUT TABLE
PINS
DESCRIPTION
74ALS (U.L.)
HIGH/LOW
LOAD VALUE
HIGH/LOW
I0 I7
Data inputs
1.0/1.0
20
A/0.1mA
S0 S2
Select inputs
1.0/1.0
20
A/0.1mA
OE
Output Enable input (active-Low)
1.0/1.0
20
A/0.1mA
Y, Y
Data outputs
130/240
2.5mA/24mA
NOTE:
One (1.0) ALS unit load is defined as: 20
A in the High state and 0.1mA in the Low state.
LOGIC SYMBOL
V
CC
= Pin 16
GND = Pin 8
SC00067
9
7
S2
OE
4
3
2
1
15
14
13
I0
I1
I2
I3
I4
I5
I6
Y
Y
5
6
12
I7
10
S1
11
S0
IEC/IEEE SYMBOL
SC00068
MUX
7
11
5
6
0
G
0
7
10
2
9
4
3
2
1
15
14
13
12
EN
Philips Semiconductors
Product specification
74ALS251
8-input multiplexer (3-State)
1991 Feb 08
3
LOGIC DIAGRAM
V
CC
= Pin 16
GND = Pin 8
SC00069
I0
I1
I2
I3
I4
I5
I6
I7
4
3
2
1
15
14
13
12
S2
S1
S0
OE
9
10
11
7
5
6
Y
Y
FUNCTION TABLE
INPUTS
OUTPUTS
S2
S1
S0
OE
Y
Y
X
X
X
H
Z
Z
L
L
L
L
I0
I0
L
L
H
L
I1
I1
L
H
L
L
I2
I2
L
H
H
L
I3
I3
H
L
L
L
I4
I4
H
L
H
L
I5
I5
H
H
L
L
I6
I6
H
H
H
L
I7
I7
H = High voltage level
L
= Low voltage level
X = Don't care
Z = High impedance "off" state
ABSOLUTE MAXIMUM RATINGS
(Operation beyond the limit set forth in this table may impair the useful life of the device.
Unless otherwise noted these limits are over the operating free air temperature range.)
SYMBOL
PARAMETER
RATING
UNIT
V
CC
Supply voltage
0.5 to +7.0
V
V
IN
Input voltage
0.5 to +7.0
V
I
IN
Input current
30 to +5
mA
V
OUT
Voltage applied to output in High output state
0.5 to V
CC
V
I
OUT
Current applied to output in Low output state
48
mA
T
amb
Operating free-air temperature range
0 to +70
C
T
stg
Storage temperature range
65 to +150
C
RECOMMENDED OPERATING CONDITIONS
SYMBOL
PARAMETER
LIMITS
UNIT
SYMBOL
PARAMETER
MIN
NOM
MAX
UNIT
V
CC
Supply voltage
4.5
5.0
5.5
V
V
IH
High-level input voltage
2.0
V
V
IL
Low-level input voltage
0.8
V
I
IK
Input clamp current
18
mA
I
OH
High-level output current
2.6
mA
I
OL
Low-level output current
24
mA
T
amb
Operating free-air temperature range
0
+70
C
Philips Semiconductors
Product specification
74ALS251
8-input multiplexer (3-State)
1991 Feb 08
4
DC ELECTRICAL CHARACTERISTICS
(Over recommended operating free-air temperature range unless otherwise noted.)
SYMBOL
PARAMETER
TEST CONDITIONS
1
LIMITS
UNIT
SYMBOL
PARAMETER
TEST CONDITIONS
1
MIN
TYP
2
MAX
UNIT
V
O
High level output voltage
V
CC
10%, V
IL
= MAX,
I
OH
= 0.4mA
V
CC
2
V
V
OH
High-level output voltage
CC
,
IL
,
V
IH
= MIN
I
OH
= 2.6mA
2.4
3.2
V
V
O
Low level output voltage
V
CC
= MIN, V
IL
= MAX,
I
OL
= 12mA
0.25
0.40
V
V
OL
Low-level output voltage
CC
,
IL
,
V
IH
= MIN
I
OL
= 24mA
0.35
0.50
V
V
IK
Input clamp voltage
V
CC
= MIN, I
I
= I
IK
0.73
1.5
V
I
I
Input current at maximum input voltage
V
CC
= MAX, V
I
= 7.0V
0.1
mA
I
IH
High-level input current
V
CC
= MAX, V
I
= 2.7V
20
A
I
IL
Low-level input current
V
CC
= MAX, V
I
= 0.4V
0.1
mA
I
OZH
Off-state output current,
High-level voltage applied
V
CC
= MAX, V
I
= 2.7V
20
A
I
OZL
Off-state output current,
Low-level voltage applied
V
CC
= MAX, V
I
= 0.4V
20
A
I
O
Output current
3
V
CC
= MAX, V
O
= 2.25V
30
112
mA
I
CC
Supply current (total)
I
CC
V
CC
= MAX
7.0
10
mA
I
CC
Supply current (total)
I
CCZ
V
CC
= MAX
9.0
14
mA
NOTES:
1. For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions for the applicable type.
2. All typical values are at V
CC
= 5V, T
amb
= 25
C.
3. The output conditions have been chosen to produce a current that closely approximates one half of the true short-circuit output current, I
OS
.
AC ELECTRICAL CHARACTERISTICS
LIMITS
SYMBOL
PARAMETER
TEST CONDITION
T
amb
= 0
C to +70
C
V
CC
= +5.0V
10%
C
L
= 50pF, R
L
= 500
UNIT
MIN
MAX
t
PLH
t
PHL
Propagation delay
In to Y
Waveform 2
4.0
4.0
12.0
12.0
ns
t
PLH
t
PHL
Propagation delay
In to Y
Waveform 1
3.0
6.0
10.0
15.0
ns
t
PLH
t
PHL
Propagation delay
Sn to Y
Waveform 1, 2
5.0
7.0
15.0
16.0
ns
t
PLH
t
PHL
Propagation delay
Sn to Y
Waveform 1, 2
8.0
5.0
17.0
15.0
ns
t
PZH
t
PZL
Propagation delay
OE to Y
Waveform 3
Waveform 4
2.0
3.0
8.0
9.0
ns
t
PHZ
t
PLZ
Propagation delay
OE to Y
Waveform 3
Waveform 4
2.0
1.0
8.0
7.0
ns
t
PZH
t
PZL
Propagation delay
OE to Y
Waveform 3
Waveform 4
2.0
3.0
8.0
9.0
ns
t
PHZ
t
PLZ
Propagation delay
OE to Y
Waveform 3
Waveform 4
2.0
1.0
8.0
7.0
ns
Philips Semiconductors
Product specification
74ALS251
8-input multiplexer (3-State)
1991 Feb 08
5
AC WAVEFORMS
For all waveforms, V
M
= 1.3V.
V
M
V
M
V
M
V
M
V
OUT
V
IN
t
PHL
t
PLH
SF00093
Waveform 1.
Propagation Delay for Inverting Output
V
M
V
M
V
M
V
M
V
OUT
V
IN
t
PLH
t
PHL
SF00092
Waveform 2.
Propagation Delay for Non-inverting Output
V
M
V
M
V
M
t
PHZ
t
PZH
OE
Y, Y
V
OH
-0.3V
0V
SC00070
Waveform 3.
3-State Output Enable Time to High Level
and Output Disable Time from High Level
V
M
V
M
V
M
t
PLZ
t
PZL
OE
Y, Y
V
OL
+0.3V
SC00071
3.5V
Waveform 4.
3-State Output Enable Time to Low Level
and Output Disable Time from Low Level
TEST CIRCUIT AND WAVEFORMS
tw
90%
VM
10%
90%
VM
10%
90%
VM
10%
90%
VM
10%
NEGATIVE
PULSE
POSITIVE
PULSE
tw
AMP (V)
0.3V
0.3V
tTHL (tf
f
)
INPUT PULSE REQUIREMENTS
Rep.Rate
t
w
t
TLH
t
THL
1MHz
500ns
2.0ns
2.0ns
Input Pulse Definition
VCC
Family
74ALS
D.U.T.
PULSE
GENERATOR
RL
CL
RT
VIN
VOUT
Test Circuit for 3-State Outputs
DEFINITIONS:
R
L
= Load resistor;
see AC electrical characteristics for value.
C
L
= Load capacitance includes jig and probe capacitance;
see AC electrical characteristics for value.
R
T
= Termination resistance should be equal to Z
OUT
of
pulse generators.
tTHL (tf
)
tTLH (tr
)
tTLH (tr
)
AMP (V)
Amplitude
3.5V
1.3V
V
M
SC00072
RL
7.0V
SWITCH POSITION
TEST
SWITCH
t
PLZ
, t
PZL
closed
All other
open
Philips Semiconductors
Product specification
74ALS251
8input multiplexer (3State)
1991 Feb 08
6
DIP16:
plastic dual in-line package; 16 leads (300 mil)
SOT38-4
Philips Semiconductors
Product specification
74ALS251
8input multiplexer (3State)
1991 Feb 08
7
SO16:
plastic small outline package; 16 leads; body width 3.9 mm
SOT109-1
Philips Semiconductors
Product specification
74ALS251
8input multiplexer (3State)
1991 Feb 08
8
Philips Semiconductors and Philips Electronics North America Corporation reserve the right to make changes, without notice, in the products,
including circuits, standard cells, and/or software, described or contained herein in order to improve design and/or performance. Philips
Semiconductors assumes no responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright,
or mask work right to these products, and makes no representations or warranties that these products are free from patent, copyright, or mask
work right infringement, unless otherwise specified. Applications that are described herein for any of these products are for illustrative purposes
only. Philips Semiconductors makes no representation or warranty that such applications will be suitable for the specified use without further testing
or modification.
LIFE SUPPORT APPLICATIONS
Philips Semiconductors and Philips Electronics North America Corporation Products are not designed for use in life support appliances, devices,
or systems where malfunction of a Philips Semiconductors and Philips Electronics North America Corporation Product can reasonably be expected
to result in a personal injury. Philips Semiconductors and Philips Electronics North America Corporation customers using or selling Philips
Semiconductors and Philips Electronics North America Corporation Products for use in such applications do so at their own risk and agree to fully
indemnify Philips Semiconductors and Philips Electronics North America Corporation for any damages resulting from such improper use or sale.
This data sheet contains preliminary data, and supplementary data will be published at a later date. Philips
Semiconductors reserves the right to make changes at any time without notice in order to improve design
and supply the best possible product.
Philips Semiconductors
811 East Arques Avenue
P.O. Box 3409
Sunnyvale, California 940883409
Telephone 800-234-7381
DEFINITIONS
Data Sheet Identification
Product Status
Definition
Objective Specification
Preliminary Specification
Product Specification
Formative or in Design
Preproduction Product
Full Production
This data sheet contains the design target or goal specifications for product development. Specifications
may change in any manner without notice.
This data sheet contains Final Specifications. Philips Semiconductors reserves the right to make changes
at any time without notice, in order to improve design and supply the best possible product.
Copyright Philips Electronics North America Corporation 1997
All rights reserved. Printed in U.S.A.
Philips
Semiconductors
PDF 
ZIP