74LS251中文资料仙童半导体数据手册PDF规格书

General Description

These data selectors/multiplexers contain full on-chip binary decoding to select one-of-eight data sources, and feature a strobe-controlled 3-STATE output. The strobe must be at a low logic level to enable these devices. The 3-STATE outputs permit direct connection to a common bus. When the strobe input is HIGH, both outputs are in a highimpedance state in which both the upper and lower transistors of each totem-pole output are OFF, and the output neither drives nor loads the bus significantly. When the strobe is LOW, the outputs are activated and operate as standard

TTL totem-pole outputs

特性 Features

■3-STATE version of DM74LS151

■Interface directly with system bus

■Perform parallel-to-serial conversion

■Permit multiplexing from N-lines to one line

■Complementary outputs provide true and inverted data

■Maximum number of common outputs: 129

■Typical propagation delay time (D to Y): 17 ns

■Typical power dissipation: 35 mW