SN74ALS640B-1N3

Buffers, Drivers, Receivers, Transceivers Overview

The SN74ALS640B-1N is an octal bus transceiver with 3-state outputs manufactured by Texas Instruments. It operates on a single 5V supply (4.5V to 5.5V) and features inverting logic for asynchronous two-way communication between data buses. The -1 suffix indicates an increased recommended maximum low-level output current (IOL) of 48 mA, provided VCC remains between 4.75V and 5.25V. Direction control determines data flow from the A bus to the B bus or vice versa, while an output-enable input isolates the buses when disabled.

Buffers, Drivers, Receivers, Transceivers Feature Summary

• Bidirectional data transfer capability between two independent 8-bit buses controlled by a direction signal
• Enhanced low-level output drive strength compared to standard versions within specific voltage ranges
• Three-state outputs allowing effective bus isolation via an independent output-enable control input

Buffers, Drivers, Receivers, Transceivers Applications

• Asynchronous two-way communication between data buses
• Bus-oriented memory and register architectures
• Clock drivers and bus controllers requiring high-drive capabilities

Buffers, Drivers, Receivers, Transceivers Procurement Notes

Verify that the ordering suffix 'N' corresponds to the Plastic Dual In-Line Package (PDIP) configuration. Confirm the '-1' designation aligns with the requirement for the increased 48 mA low-level output current specification. Ensure the application environment maintains the supply voltage between 4.75V and 5.25V to fully utilize this enhanced drive characteristic as defined in the datasheet.

Buffers, Drivers, Receivers, Transceivers Selection Notes

Select this component when designing systems requiring bidirectional octal data transfer with high-drive capacity. The -1 version is specifically suited for applications demanding higher low-level sink currents than the standard SN74ALS640B provides. Consider the PDIP package constraints if surface-mount alternatives are not required. Verify compatibility with TTL input levels and 3-state bus requirements.

Buffers, Drivers, Receivers, Transceivers Part Context

This device belongs to the Texas Instruments 74ALS series of logic components, designed for high-speed digital applications. It is part of the broader family of octal bus transceivers, sharing functional similarities with other ALS devices but distinguished by its specific drive characteristics and package options. The SN74ALS640B-1N represents the commercial temperature range variant housed in a through-hole DIP package.

Buffers, Drivers, Receivers, Transceivers Replacement Considerations

• SN74ALS640BN
• SN74ALS640B-1DWR
• SN74ALS640B-1NSR

Buffers, Drivers, Receivers, Transceivers FAQ

What distinguishes the SN74ALS640B-1N from the standard SN74ALS640B?

The -1 version features an increased recommended maximum low-level output current (IOL) of 48 mA, whereas the standard version is rated for 24 mA. This enhancement applies only when the supply voltage is maintained between 4.75V and 5.25V.

How does the output-enable input function?

When the output-enable (OE) input is held high, the device enters an isolation state, effectively disconnecting the internal circuitry from the buses regardless of the direction control setting.