SN74LS251是TI公司的一款解码器/编码器/多路复用器产品，SN74LS251是具有三态输出的 8 线路到 1 线路数据选择器/多路复用器，本页介绍了SN74LS251的产品说明、应用、特性等，并给出了与SN74LS251相关的TI元器件型号供参考。
SN74LS251 - 具有三态输出的 8 线路到 1 线路数据选择器/多路复用器 - 解码器/编码器/多路复用器 - 特殊逻辑 - TI公司（Texas Instruments，德州仪器）
These monolithic data selectors/multiplexers contain full on-chip binary decoding to select one-of-eight data sources and feature a strobe-controlled three-state output. The strobe must be at a low logic level to enable these devices. The three-state outputs permit a number of outputs to be connected to a common bus. When the strobe input is high, both outputs are in a high-impedance 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.
To minimize the possibility that two outputs will attempt to take a common bus to opposite logic levels, the output control circuitry is designed so that the average output disable time is shorter than the average output enable time. The SN54251 and SN74251 have output clamp diodes to attenuate reflections on the bus line.
- Three-State Versions of '151, 'LS151, 'S151
- Three State Outputs 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
- Fully Compatible with Most TTL Circuits
