DM74ALS251N

Overview

The DM74ALS251N is an octal data selector/multiplexer manufactured by Fairchild Semiconductor under the Advanced Low-power Schottky (ALS) logic series. It features eight non-inverting inputs, three address select lines, and a single 3-state output. The device operates within a supply voltage range of 4.5 V to 5.5 V and supports surface-mount or through-hole installation in a standard DIP-24 package. Propagation delay is specified at 15 ns at 4.5 V to 5.5 V, with an operating temperature range from 0°C to +70°C.

Feature Summary

• Provides multiplexing functionality for eight independent data lines into a single output channel
• Features 3-state output capability allowing bus isolation when disabled
• Utilizes Advanced Low-power Schottky process for improved AC performance over LS counterparts

Applications

• Data routing in microprocessor systems
• Memory addressing and selection circuits
• Asynchronous bidirectional data buses

Procurement Notes

Verify component authenticity and datasheet revision status due to potential manufacturing transitions between Fairchild Semiconductor and onsemi. Confirm package integrity and pin compatibility during integration. Check RoHS compliance documentation as specifications may vary by production batch. Ensure proper handling procedures are followed given the component's age and availability constraints.

Selection Notes

Select this component when an octal multiplexer with 3-state outputs is required for ALS logic family designs. Verify that the 15 ns propagation delay meets system timing requirements. Ensure the DIP-24 package fits the target PCB layout. Compare against similar devices like the DM74ALS253 if fewer channels are sufficient for the application design.

Part Context

This part belongs to the Fairchild DM74ALS series, which implements Advanced Low-power Schottky TTL technology. The series offers switching speed improvements over standard LS logic while maintaining lower power consumption than original Schottky TTL devices. The DM74ALS251 specifically addresses applications requiring high-speed data selection among multiple input sources.

Replacement Considerations

Check for equivalents such as the DM74ALS251MX or DM74ALS251SJ. Verify functional compatibility with other manufacturers' 74ALS251 variants before substitution.