DM74S240N

Overview

The DM74S240N is an octal three-state buffer and line driver manufactured by Fairchild Semiconductor. It features two independent four-bit channels with inverted outputs, housed in a 20-pin dual in-line package (DIP). The device operates within a supply voltage range of 4.75 V to 5.25 V. Key electrical parameters include a maximum propagation delay of 10 ns at 5 V with a 150 pF load, high-level output current of 15 mA, and low-level output current of 64 mA. Logic levels are defined as 0.8 V for low and 2 V for high. It supports through-hole mounting and functions within an operating temperature range of 0°C to 70°C.

Feature Summary

• Provides bidirectional or unidirectional buffering capabilities via eight three-state buffers organized into two groups of four.
• Features inverted outputs designed to drive terminated transmission lines with low impedance characteristics.
• High input impedance prevents significant loading of the transmission line during operation.

Applications

• Memory system bus interfacing
• Microprocessor system data routing
• Communication systems signal buffering

Procurement Notes

Verify the manufacturer origin carefully, as the DM74S240N designation is produced by multiple vendors including Texas Instruments and ON Semiconductor. Confirm that the specific unit matches the Fairchild Semiconductor Advanced Schottky specifications regarding pinout compatibility and electrical performance limits before integration.

Selection Notes

Select this component when designing systems requiring fast switching speeds with lower power dissipation compared to standard Schottky TTL counterparts. Ensure the application environment remains within the specified commercial temperature range and utilizes a stable 5 V power supply to maintain signal integrity across the inverted outputs.

Part Context

This part belongs to the DM74AS family of Advanced Schottky logic circuits. It shares functional and pin compatibility with 74LS and standard Schottky counterparts, allowing for direct replacement in existing designs while offering improved switching response and reduced power consumption.

Replacement Considerations

The DM74AS240N serves as a direct functional substitute within the same Advanced Schottky family. Verify that alternative sources provide identical DIP-20 packaging and meet the original 10 ns propagation delay specification under equivalent load conditions.