SN74ALS640BNS

Buffers, Drivers, Receivers, Transceivers Overview

The SN74ALS640BNS is an octal bus transceiver with 3-state outputs manufactured by Texas Instruments. It operates within a supply voltage range of 4.5 V to 5.5 V and supports a maximum propagation delay of 11 ns at VCC = 5.5 V. The device provides a low-level output current (IOL) of 24 mA and a high-level output current (IOH) of -15 mA. It is housed in a 20-pin Small-Outline Package (SOP/NS) and functions over an operating temperature range of 0°C to 70°C.

Buffers, Drivers, Receivers, Transceivers Feature Summary

• Bidirectional data transmission between two independent 8-bit buses controlled by a single direction input
• Asynchronous communication capability with dedicated output-enable control for effective bus isolation
• Inverting logic configuration providing three-state outputs for direct system bus interfacing

Buffers, Drivers, Receivers, Transceivers Applications

• Asynchronous two-way communication between data buses
• Bus-oriented memory and command decoders
• High-density digital systems requiring bidirectional data transfer

Buffers, Drivers, Receivers, Transceivers Procurement Notes

Verify the specific ordering suffix 'NS' corresponds to the 20-pin SOP package when sourcing. Confirm that the component meets the required RoHS compliance status as indicated in the manufacturer's packaging information. Ensure the procurement channel sources production-active parts rather than obsolete variants within the same family.

Buffers, Drivers, Receivers, Transceivers Selection Notes

Select this component for applications requiring standard TTL-compatible inputs and outputs with moderate drive strength. The ALS series offers improved speed compared to LS logic while maintaining lower power consumption. Verify that the 20-pin SOP footprint aligns with the target PCB layout constraints and thermal requirements.

Buffers, Drivers, Receivers, Transceivers Part Context

This part belongs to the SN54/74ALS640B family of octal bus transceivers. It shares functional similarities with the SN74AS640 but utilizes Advanced Low-power Schottky technology. The device is designed for general-purpose digital logic applications where reliable bidirectional data flow is necessary.

Buffers, Drivers, Receivers, Transceivers Replacement Considerations

SN74ALS640BN (PDIP package)

Buffers, Drivers, Receivers, Transceivers FAQ

How does the Output Enable (OE) input affect the device operation?

When the OE input is high, the device is disabled, effectively isolating the A and B buses regardless of the direction control state.

What is the function of the DIR input?

The Direction (DIR) input determines the signal flow; a low level directs data from the B bus to the A bus, while a high level directs data from the A bus to the B bus.