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 busoriented

system.