Philips N74ALS251D, N74ALS251N Datasheet

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74ALS251

8–input multiplexer (3–State)

Product specification
IC05 Data Handbook

1991 Feb 08

INTEGRATED CIRCUITS

Philips Semiconductors Product specification

74ALS2518-input multiplexer (3-State)

2

1991 Feb 08 853–1377 01670

FEA TURES

•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
107

6

5

4

3

2

1

OE

V

CC

I7
S0
S1

I6

I4
I5

I3
I2

Y

I1
I0

Y

98GND S2

SC00066

ORDERING INFORMA TION

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 20µA/0.1mA

S0 – S2 Select inputs 1.0/1.0 20µA/0.1mA

OE Output Enable input (active-Low) 1.0/1.0 20µA/0.1mA

Y, Y Data outputs 130/240 2.5mA/24mA

NOTE: One (1.0) ALS unit load is defined as: 20µA in the High state and 0.1mA in the Low state.

LOGIC SYMBOL

VCC = Pin 16
GND = Pin 8

SC00067

9
7

S2
OE

4 3 2 1 15 14 13

I0 I1 I2 I3 I4 I5 I6

YY

56

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

74ALS2518-input multiplexer (3-State)

1991 Feb 08

3

LOGIC DIAGRAM

VCC = 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

56

YY

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

LIMITS

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