SLS SL74HC251D, SL74HC251N Datasheet

SL74HC251

Semiconductor

8-Input Data Selector/Multiplexer with 3-State Outputs

High-Performance Silicon-Gate CMOS

The SL74HC251 is identical in pinout to the LS/ALS251. The device
inputs are compatible with standard CMOS outputs; with pullup
resistors, they are compatible with LS/ALSTTL outputs.

The device selects one of the eight binary Data Inputs, as
determined by the Address Inputs. The Output Enable pin must be at a
low level for the selected data to appear at the outputs. If Output
Enable is high, the Y and the Y outputs are in the high-impedance state.
This 3-State feature allows the IN74HC251 to be used in bus-oriented
systems.

• Outputs Directly Interface to CMOS, NMOS, and TTL

• Operating Voltage Range: 2.0 to 6.0 V

• Low Input Current: 1.0 µA

• High Noise Immunity Characteristic of CMOS Devices

ORDERING INFORMATION

SL74HC251N Plastic

SL74HC251D SOIC

TA = -55° to 125° C for all packages

LOGIC DIAGRAM

PIN 16 =VCC

PIN 8 = GND

PIN ASSIGNMENT

FUNCTION TABLE

Inputs Outputs

A2 A1 A0 OE Y Y

X X X H Z Z

L L L L D0 D0
L L H L D1 D1
L H L L D2 D2

L H H L D3 D3
H L L L D4 D4
H L H L D5 D5
H H L L D6 D6

SLS

H H H L D7 D7

D0,D1...D7=the level of the respective D
input
Z = high-impedance state
X = don’t care

System Logic

SL74HC251

Semiconductor

MAXIMUM RATINGS*

Symbol Parameter Value Unit

VCC DC Supply Voltage (Referenced to GND) -0.5 to +7.0 V
VIN DC Input Voltage (Referenced to GND) -1.5 to VCC +1.5 V

V

DC Output Voltage (Referenced to GND) -0.5 to VCC +0.5 V

OUT

IIN DC Input Current, per Pin ±25 mA

I

DC Output Current, per Pin ±50 mA

OUT

ICC DC Supply Current, VCC and GND Pins ±75 mA
PD Power Dissipation in Still Air, Plastic DIP+

SOIC Package+

750
500

Tstg Storage Temperature -65 to +150 °C

TL Lead Temperature, 1 mm from Case for 10 Seconds

260 °C

(Plastic DIP or SOIC Package)

*

Maximum Ratings are those values beyond which damage to the device may occur.

Functional operation should be restricted to the Recommended Operating Conditions.
+Derating - Plastic DIP: - 10 m W/°C from 65° to 125°C

SOIC Package: : - 7 mW/°C from 65° to 125°C

RECOMMENDED OPERATING CONDITIONS

Symbol Parameter Min Max Unit

VCC DC Supply Voltage (Referenced to GND) 2.0 6.0 V

VIN, V

DC Input Voltage, Output Voltage (Referenced to GND) 0 VCC V

OUT

TA Operating Temperature, All Package Types -55 +125 °C

tr, tf Input Rise and Fall Time (Figure 1) VCC =2.0 V

VCC =4.5 V
V

=6.0 V

CC

0

1000
0
0

500
400

mW

ns

This device contains protection circuitry to guard against damage due to high static voltages or electric
fields. However, precautions must be taken to avoid applications of any voltage higher than maximum rated
voltages to this high-impedance circuit. For proper operation, VIN and V
GND≤(VIN or V

OUT

)≤VCC.

should be constrained to the range

OUT

Unused inputs must always be tied to an appropriate logic voltage level (e.g., either GND or VCC).
Unused outputs must be left open.

System Logic

SLS