DM74ALS646NT

Overview

The DM74ALS646NT is an octal 3-state bus transceiver and register manufactured by Fairchild Semiconductor. It belongs to the Advanced Low-power Schottky (ALS) logic family, designed for high-speed digital applications. The device integrates eight D-type flip-flops with tri-state outputs, allowing data storage and bidirectional transmission on a single bus line. It operates within a standard voltage range typical for TTL-compatible logic circuits.

Feature Summary

• Integrates octal bus transceiver functionality with D-type register capability in a single package
• Features advanced low-power Schottky technology for improved switching speed and reduced power consumption
• Provides three-state outputs to isolate the bus when disabled

Applications

• Memory mapping controllers
• Clock drivers
• Bus-oriented architectures

Procurement Notes

Verify the manufacturer origin as Fairchild Semiconductor or its successor entities like onsemi, as production rights may have transferred. Confirm the specific suffix 'NT' corresponds to the intended tape-and-reel packaging format if required for automated assembly. Ensure the component meets current environmental compliance standards such as RoHS, noting that older Fairchild datasheets may not reflect modern regulatory updates.

Selection Notes

Select this component when a design requires both temporary data storage and bidirectional bus driving capabilities. The ALS series offers a balance between speed and power dissipation suitable for general-purpose digital systems. Consider the pinout compatibility with other 74-series devices if replacing legacy components in existing board layouts.

Part Context

This part is part of the extensive 74ALS logic family, widely used in industrial and consumer electronics during the late 20th century. The DM74ALS646 specifically combines the utility of a bus transceiver with a latch, reducing component count in complex digital interfaces compared to using separate transceiver and register ICs.

Replacement Considerations

• DM74ALS646N
• DM74ALS646M