onsemi

SN74LS38D

SN74LS38D Description

The SN74LS38D from onsemi is a quad 2-input NAND gate with open-collector outputs, housed in a 14-pin SOIC package. Designed for surface-mount applications, it operates within a 4.75V to 5.25V supply range, making it compatible with standard TTL logic levels. With a maximum propagation delay of 32ns at 5V and 45pF load, it offers reliable performance for moderate-speed digital circuits. The device features low power consumption, drawing a maximum quiescent current of 2 mA, and supports input logic levels of 0.8V (Low) and 2V (High). Though marked as obsolete, it remains relevant for legacy systems and specific industrial applications.

SN74LS38D Features

• Open-Collector Outputs: Allows wired-AND configurations and direct drive of higher-voltage loads (e.g., relays, LEDs).
• Low Power Consumption: Ideal for battery-powered or energy-efficient designs.
• TTL Compatibility: Ensures seamless integration with 5V logic systems.
• Quad NAND Configuration: Four independent gates in a compact SOIC package, saving board space.
• Robust Performance: Operates reliably across 0°C to 70°C, suitable for commercial environments.
• High Noise Immunity: TTL-level inputs provide stability in electrically noisy conditions.

SN74LS38D Applications

• Industrial Control Systems: Used in logic-level shifting and signal conditioning due to open-collector flexibility.
• Automotive Electronics: Interfaces between low-voltage logic and higher-voltage actuators (e.g., solenoids).
• Legacy Equipment Maintenance: Replaces older 74LS-series components in repairs or upgrades.
• Prototyping & Education: Demonstrates basic logic gate behavior in academic or DIY projects.
• LED/Display Driving: Open-collector outputs simplify current sinking for indicator lights.

Conclusion of SN74LS38D

The SN74LS38D is a versatile NAND gate IC offering a balance of speed, power efficiency, and interface flexibility. Its open-collector outputs and TTL compatibility make it particularly useful for mixed-voltage systems and wired logic applications. While newer alternatives exist, its proven reliability ensures continued use in industrial, automotive, and educational contexts where legacy support is critical. Engineers valuing simplicity and backward compatibility will find this IC a pragmatic choice.