DM74ALS646WMX

Overview

The DM74ALS646WMX is an octal bus transceiver from the Advanced Low-power Schottky (ALS) logic family, manufactured by Fairchild Semiconductor. It features eight pairs of three-state logic elements configured for bidirectional data transfer between buses. The device operates with a supply voltage range of 4.5 V to 5.5 V and utilizes TTL-compatible input and output levels. It is housed in a 24-lead SOIC package with a width of 0.300 inches. The component supports a maximum operating temperature of +70 °C and includes direction control functionality managed by a dedicated DIR input pin.

Feature Summary

• Octal configuration providing eight independent bidirectional data paths for efficient bus interfacing
• Three-state outputs allowing direct connection to system buses without additional buffering
• Direction control via a single DIR input pin to manage data flow between A and B buses
• Advanced Low-power Schottky technology ensuring high-speed operation with reduced power consumption

Applications

• Memory systems requiring high-speed data transfer
• Microprocessor-based systems utilizing asynchronous bidirectional data buses
• Two-way communication interfaces between different bus architectures

Procurement Notes

Verify the specific suffix 'MX' against the manufacturer's current datasheet to confirm package dimensions and lead finish specifications. Ensure compatibility with existing PCB footprints for the 24-lead SOIC format. Confirm that the ALS series availability aligns with long-term procurement strategies, as legacy logic families may have limited production runs compared to modern CMOS alternatives.

Selection Notes

Select this component when designing systems that require robust bidirectional data transmission with moderate speed requirements typical of the ALS family. It is suitable for applications where TTL-level compatibility is necessary but lower power dissipation than standard LS logic is desired. Consider the 24-lead SOIC package constraints during layout planning to ensure adequate thermal management within the specified operating temperature range.

Part Context

This part belongs to the DM74ALS series, representing Fairchild's implementation of Advanced Low-power Schottky logic. It serves as a successor to earlier LS devices, offering improved speed-to-power ratios. The DM74ALS646 variant specifically addresses the need for wide bus transceivers in complex digital systems, bridging the gap between simple buffers and high-performance AS series components.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation.