DM74ALS540AN

Overview

The DM74ALS540AN is an octal inverting buffer and line driver manufactured by onsemi, featuring 3-STATE outputs. It utilizes a 2-input NOR gate for control, placing all eight outputs in a high impedance state if either G1 or G2 is HIGH. The device employs an advanced oxide-isolated, ion-implanted Schottky TTL process with P-N-P inputs to reduce DC loading. It operates within a supply voltage range of 4.5V to 5.5V and supports a free-air operating temperature from 0°C to +70°C.

Feature Summary

• Features a data flow-thru pinout configuration where all inputs are located on the opposite side of the package from the outputs to enhance printed circuit board layout.
• Incorporates a 2-input NOR gate control mechanism that forces all outputs into a high impedance state when either control input is HIGH.
• Utilizes P-N-P inputs designed to minimize DC loading on driving circuits.

Applications

• High-performance memory mapping
• Clock buffering and distribution
• TTL-to-CMOS translation

Procurement Notes

Verify the specific ordering code suffix to confirm the package type, as the DM74ALS540A series is available in multiple configurations including SOIC and SOP. Ensure the selected variant matches the required physical dimensions and lead pitch for the target application. Confirm availability status as older logic families may have limited production runs.

Selection Notes

Select this component when a bidirectional octal bus driver with inverted logic is required alongside a pinout that separates inputs and outputs for easier routing. The ALS technology provides faster switching speeds compared to standard LS logic while maintaining compatible power consumption levels suitable for dense digital systems.

Part Context

This part belongs to the 74ALS (Advanced Low-power Schottky) logic family, known for improved speed over standard TTL. The 'DM' prefix indicates it is a commercial grade device originally produced by Fairchild Semiconductor, now managed under the onsemi portfolio. It serves as a functional equivalent to other octal buffers in the industry.

Replacement Considerations

Direct substitutes include SN74ALS540N from Texas Instruments. Verify pin compatibility and electrical characteristics against the original datasheet before implementation.

FAQ

How does the 3-STATE control function operate?

The control gate consists of a 2-input NOR configuration. If either G1 or G2 is set to a HIGH logic level, all eight outputs enter a high impedance state regardless of the input signals.

What is the significance of the data flow-thru pinout?

The data flow-thru design places all inputs on one side of the package and all outputs on the opposite side. This arrangement simplifies printed circuit board layout by allowing straight-through signal paths without crossovers.