SN74ALS638ADW

Buffers, Drivers, Receivers, Transceivers Overview

The SN74ALS638ADW is an octal bus transceiver from the Texas Instruments ALS logic family, housed in a 20-pin Small Outline (DW) package. It facilitates asynchronous two-way communication between open-collector and 3-state buses. The A-bus outputs are open collector, while B-bus outputs are 3-state. Data transmission direction is controlled by the DIR input, allowing transfer from A to B or B to A. An OE input isolates the buses when disabled. The device operates within a supply voltage range of 4.5 V to 5.5 V and supports a low-level output current of 24 mA.

Buffers, Drivers, Receivers, Transceivers Feature Summary

• Bidirectional data transmission between open-collector and 3-state buses
• Direction control via DIR input for A-to-B or B-to-A flow
• Bus isolation capability through OE input
• Mixed output types with open-collector A ports and 3-state B ports

Buffers, Drivers, Receivers, Transceivers Applications

• Asynchronous two-way communication systems
• Interfacing open-collector buses with 3-state buses
• Data routing in high-density digital circuits

Buffers, Drivers, Receivers, Transceivers Procurement Notes

Verify the specific ordering suffix against the manufacturer's latest Package Option Addendum to confirm active status and packaging details. Ensure compatibility with the required operating temperature range and voltage specifications before integration into designs.

Buffers, Drivers, Receivers, Transceivers Selection Notes

Select this component for applications requiring mixed open-collector and 3-state bus interfacing. Consider the ALS series characteristics for speed and power consumption balance. Verify that the 20-pin SOIC package fits the board layout constraints and thermal requirements.

Buffers, Drivers, Receivers, Transceivers Part Context

This device belongs to the SN74ALS638A/639A series of octal bus transceivers. It is part of the broader 74ALS logic family, designed for high-speed digital applications. The DW package variant provides a surface-mount solution suitable for modern PCB assembly techniques.

Buffers, Drivers, Receivers, Transceivers FAQ

What is the difference between the A-bus and B-bus outputs?

The A-bus outputs are open-collector type, while the B-bus outputs are 3-state type.

How is the data direction controlled?

The direction is determined by the logic level at the DIR input, selecting whether data flows from the A bus to the B bus or vice versa.