SN74HC151D – TEXAS INSTRUMENTS

The SN74HC151D is a high-speed CMOS 8-input multiplexer/selector with 3-state outputs, packaged in a space-saving 16-pin DIP or SOIC. Operating from a wide voltage range of 2V to 6V, it offers low power consumption and high noise immunity characteristic of HC CMOS logic. This device selects one of eight inputs (A0-A7) based on the three binary select inputs (S0-S2), presenting the selected input at the Y output. The output is enabled/disabled via the OE (Output Enable) pin; a high OE enables the output, while a low OE places the output in a high-impedance state, crucial for bussing applications. Propagation delays are typically under 15ns at VCC = 5V._x000D_
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Its key advantage lies in its ability to route one of eight signals to a common output, simplifying signal switching and routing in digital systems. Common applications include data selection in microcontrollers, address decoding, and implementing complex logic functions with fewer gates. The 3-state output feature allows multiple SN74HC151Ds to share a common bus without contention, enhancing system scalability. Designers should note that while it offers high speed, it’s not suitable for high-frequency applications exceeding its specified maximum operating frequency. Careful consideration of input capacitance (typically 4pF) is also necessary in high-speed designs.