DM74ALS640AWM

Overview

The DM74ALS640AWM is an inverting octal bus transceiver manufactured by onsemi, utilizing the Advanced Oxide-isolated Ion-implanted Schottky TTL process. It facilitates asynchronous two-way communication between data busses, transmitting data from the A bus to the B bus or vice versa based on the direction control (DIR) input level. The enable input (G) isolates the busses when disabled. Packaged in a 20-Lead Small Outline Integrated Circuit (SOIC), it operates within a supply voltage range of 4.5V to 5.5V and supports a temperature range of 0°C to +70°C.

Feature Summary

• Advanced Oxide-isolated Ion-implanted Schottky TTL process
• Switching performance guaranteed over full temperature and VCC supply range
• PNP input design reduces input loading

Applications

• Asynchronous two-way communication between data busses

Procurement Notes

Verify component authenticity through authorized channels as this part may be discontinued. Confirm package type M20B matches requirements. Check RoHS compliance status for specific manufacturing lots. Ensure operating conditions align with datasheet limits. Validate replacement availability if sourcing new production units.

Selection Notes

Select this component for applications requiring bidirectional data transfer with inversion. Consider the SOIC-20 package for surface mount assembly. Evaluate propagation delay specifications against system timing requirements. Verify power supply stability within the 4.5V to 5.5V range. Assess thermal management needs for the specified operating temperature range.

Part Context

This device belongs to the 74ALS logic family, known for improved speed over standard TTL. The DM74ALS640A variant specifically provides octal bus transceiver functionality. It is designed for general-purpose digital systems requiring isolated bidirectional data paths. The manufacturer history includes Fairchild Semiconductor and onsemi.

Replacement Considerations

SN74ALS640DW Texas Instruments

FAQ

What determines the direction of data flow?

Data flows from A to B when DIR is HIGH, and from B to A when DIR is LOW.

How is the device disabled?

Setting the enable input (G) to HIGH disables the outputs, effectively isolating the busses.