DM74ALS240AN

Overview

The DM74ALS240AN is an octal 3-STATE bus driver manufactured by onsemi, utilizing the Advanced Low Power Schottky (ALS) TTL process. It operates within a supply voltage range of 4.5V to 5.5V and supports a low-level output drive current of 24mA. The device features two separate groups of four buffers with symmetric enable gating controlled by logic LOW inputs. It includes power-up/down protection to maintain outputs in a high-impedance state during supply ramping. The component is housed in a 20-Lead Plastic Dual-In-Line Package (PDIP).

Feature Summary

• Octal 3-STATE bus drivers designed for memory, microprocessor, or communication system interfaces.
• Functional and pin compatible with DM74LS counterparts while offering improved switching performance.
• PNP input design reduces input loading compared to standard TTL devices.
• Outputs remain in a high-impedance state during power supply ramp-up or ramp-down to eliminate bus glitching.

Applications

• Bus interface implementation for memory systems.
• Data routing in microprocessor architectures.
• Communication system signal buffering.

Procurement Notes

Verify the obsolete status of this component before procurement planning. Confirm availability through authorized distributors or surplus channels as it may no longer be in active production. Ensure that any replacement components meet the required ALS specifications and package dimensions to maintain compatibility with existing designs.

Selection Notes

Select this component when designing systems requiring octal bus drivers with 3-STATE capabilities. It is suitable for applications needing compatibility with LS-TTL logic levels but demanding lower power consumption. Consider the PDIP package constraints for board layout and verify that the operating temperature range meets environmental requirements.

Part Context

This part belongs to the DM74ALS240A series, which includes variants such as SOIC and SOP packages. The 'N' suffix specifically denotes the 20-Lead Plastic Dual-In-Line Package (PDIP). The series is based on Fairchild Semiconductor's original design, now maintained under the onsemi brand portfolio.

Replacement Considerations

SN74ALS245A-1N and SN74ALS245AN from Texas Instruments are listed as parameter equivalent alternatives.

FAQ

How does the DM74ALS240AN handle power-up conditions?

The 3-STATE circuitry maintains buffer outputs in a high-impedance state during power supply ramp-up or ramp-down, eliminating bus glitching problems.

What is the control logic for the outputs?

The control inputs symmetrically enable the respective outputs when set to logic LOW.