74AC251SJ

Signal Switches, Multiplexers, Decoders Overview

The onsemi 74AC251SJ is an 8-input digital multiplexer with 3-STATE outputs, manufactured using high-speed CMOS technology. It operates within a supply voltage range of 2.0V to 6.0V and supports an operating temperature range of -40°C to +85°C. The device features both true (Z) and complementary (Z-bar) outputs, each capable of sourcing or sinking up to 24 mA. Propagation delays from select inputs to output are typically 8.5 ns at 5.0V, while input-to-output delays are typically 7.0 ns. The component is housed in a 16-Lead Small Outline Package (SOP), EIAJ TYPE II, measuring 5.3mm wide.

Signal Switches, Multiplexers, Decoders Feature Summary

• Provides multifunctional capability as an 8-input multiplexer or universal function generator for four variables.
• Includes on-chip select logic decoding to manage data selection from eight sources.
• Features inverting and noninverting 3-STATE outputs that allow bus expansion by tying multiple devices together.

Signal Switches, Multiplexers, Decoders Applications

• Selecting one bit of data from up to eight independent sources.
• Generating any logic function of four variables as a universal function generator.
• Expanding multiplexer systems by connecting outputs of multiple devices to a common bus.

Signal Switches, Multiplexers, Decoders Procurement Notes

Verify the specific ordering suffix 'SJ' corresponds to the 16-Lead SOP package (M16D) rather than other variants like SC or PC. Confirm RoHS compliance status through official manufacturer documentation, as historical batches may vary. Ensure the design accounts for the 3-STATE enable logic requirements to prevent bus contention when integrating this component into larger systems.

Signal Switches, Multiplexers, Decoders Selection Notes

Choose the 74AC251SJ over the 74ACT251 variant if operation below 4.5V is required, as the AC series supports voltages down to 2.0V. Select this part for applications requiring both true and complementary outputs simultaneously. Consider the SOP package dimensions if board space is constrained compared to DIP or TSSOP options.

Signal Switches, Multiplexers, Decoders Part Context

This component belongs to the 74AC family of high-speed CMOS logic devices. It serves as a standard solution for data routing and logic generation in digital circuits. The device was originally developed by Fairchild Semiconductor and is now distributed under the onsemi brand portfolio, maintaining compatibility with established 74-series logic standards.

Signal Switches, Multiplexers, Decoders Replacement Considerations

The 74AC251SC offers identical functionality in a 16-Lead SOIC package. The 74AC251PC provides the same electrical characteristics in a 16-Lead PDIP package. The 74AC251MTC is available in a 16-Lead TSSOP package for different form factor requirements.

Signal Switches, Multiplexers, Decoders FAQ

How does the Output Enable (OE) pin control the state of the outputs?

The OE pin is active LOW. When HIGH, both Z and Z-bar outputs enter a high impedance state. When LOW, the selected input data is passed to the outputs based on the S0-S2 select lines.

Can multiple 74AC251SJ devices be connected to the same bus?

Yes, the 3-STATE outputs allow for expansion. Up to 128 devices can be tied together, provided their Output Enable signals are designed to ensure no overlap in the active-LOW portion to avoid high currents.