CDx4HC251, CDx4HCT251 High-Speed CMOS Logic 8-Input Multiplexer, Three-State

1 Features

• Selects one of eight binary data inputs

• Three-state output capability

• True and complement outputs

• Typical (data to output) propagation delay of 14 ns

at VCC = 5 V, CL = 15 pF, TA = 25 ℃

• Fanout (over temperature range)

– Standard outputs : 10 LSTTL loads

– Bus driver outputs : 15 LSTTL loads

• Wide operating temperature range : – 55

℃ to 125

℃

• Balanced propagation delay and transition times

• Significant power reduction compared to LSTTL

logic ICs

• Alternate source is Philips

• HC types

– 2 V to 6 V operation

– High noise immunity : NIL = 30 %, NIH = 30% of

VCC at VCC = 5 V

• HCT types

– 4.5 V to 5.5 V operation

– Direct LSTTL input logic compatibility, VIL = 0.8

V (Max), VIH = 2 V (Min)

– CMOS input compatibility, II ≤ 1 μA at VOL, VOH

2 Description

The ’HC251 and ’HCT251 are 8-channel digital

multiplexers with three-state outputs, fabricated with

high-speed silicongate CMOS technology. Together

with the low power consumption of standard CMOS

integrated circuits, they possess the ability to drive

10 LSTTL loads. The three-state feature makes them

ideally suited for interfacing with bus lines in a bus-

oriented system.

Device Information

PART NUMBER

PACKAGE(1)

BODY SIZE (NOM)

CD54HC251F

CDIP (16)

24.38 mm × 6.92 mm

CD54HCT251F

CDIP (16)

24.38 mm × 6.92 mm

CD74HC251M

SOIC (16)

9.90 mm × 3.90 mm

CD74HCT251M

SOIC (16)

9.90 mm × 3.90 mm

CD74HC251E

PDIP (16)

19.31 mm × 6.35 mm

CD74HCT251E

PDIP (16)

19.31 mm × 6.35 mm

(1)

For all available packages, see the orderable addendum at

the end of the data sheet.

S0

S1

S2

I0

I1

I2

I3

I4

I5

I6

I7

Y

Y

OE

Functional Block Diagram

CD54HC251, CD74HC251, CD54HCT251, CD74HCT251

SCHS169D – NOVEMBER 1998 – REVISED MARCH 2022

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.