SN74ALS621A-1N

Buffers, Drivers, Receivers, Transceivers Overview

The SN74ALS621A-1N is an octal bus transceiver from the Texas Instruments ALS logic family, designed for asynchronous two-way communication between data buses. It features open-collector true outputs and a dual-enable configuration allowing flexible timing control. The -1 suffix indicates an increased recommended maximum low-level output current of 48 mA when VCC is between 4.75 V and 5.25 V. It operates within a supply voltage range of 4.5 V to 5.5 V and supports propagation delays up to 33 ns.

Buffers, Drivers, Receivers, Transceivers Feature Summary

• Supports asynchronous bidirectional data transmission between A and B buses
• Features open-collector true outputs with enhanced drive capability in the -1 version
• Dual-output enable inputs allow isolation or simultaneous bus-latch functionality

Buffers, Drivers, Receivers, Transceivers Applications

• Asynchronous two-way communication between data buses
• Bus-oriented memory and command decoding applications
• Post buffering and driver circuits

Buffers, Drivers, Receivers, Transceivers Procurement Notes

Verify the specific ordering suffix '-1' to confirm the device meets the requirement for the increased 48 mA low-level output current specification. Ensure the package type matches the design requirements, as this part number corresponds to the standard plastic DIP (N) package. Confirm RoHS compliance status and lead finish details via the manufacturer's official documentation before finalizing procurement.

Buffers, Drivers, Receivers, Transceivers Selection Notes

Select the SN74ALS621A-1N over the standard SN74ALS621A only if the application requires the higher 48 mA low-level output current capability under specific voltage conditions. Consider the open-collector output nature, which requires external pull-up resistors, unlike the three-state versions in the same family. Evaluate the 33 ns maximum propagation delay against system timing constraints.

Buffers, Drivers, Receivers, Transceivers Part Context

This component belongs to the SN74ALS62xA series of octal bus transceivers manufactured by Texas Instruments. It shares the same functional architecture as the SN74ALS620A and SN74ALS623A but differs in output structure. While the SN74ALS620A provides inverting three-state outputs and the SN74ALS623A provides non-inverting three-state outputs, the SN74ALS621A specifically provides non-inverting open-collector outputs.

Buffers, Drivers, Receivers, Transceivers Replacement Considerations

The SN74ALS621AN is the standard version without the enhanced current rating. The SN74ALS621ADW offers the same function in a SOIC package.