The National Semiconductor 54S140FM is a high-speed, low-power Schmitt-trigger hex inverter designed for use in a variety of digital applications. This device is part of the 54S series, which is known for its robust performance and reliability in military and aerospace environments. The 54S140FM is particularly valued for its ability to provide clean, fast signal transitions, making it ideal for applications where noise immunity and signal integrity are critical.

## Overview

The 54S140FM features six independent Schmitt-trigger inverters, which are capable of transforming slow input signals into sharply defined, jitter-free output signals. This characteristic is particularly useful in applications where the input signal may be noisy or slow, as the Schmitt-trigger design helps to eliminate false triggering and ensures reliable operation.

## Key Specifications

1. Device Type: Hex Schmitt-Trigger Inverter

2. Supply Voltage (V_CC):
- Operating range: 3V to 15V

3. Input Voltage Levels:
- Minimum input high voltage (V_IH): 2.0V (for V_CC = 5V)
- Maximum input low voltage (V_IL): 0.8V (for V_CC = 5V)

4. Output Voltage Levels:
- Minimum output high voltage (V_OH): V_CC - 0.1V (for V_CC = 5V)
- Maximum output low voltage (V_OL): 0.1V (for V_CC = 5V)

5. Input Current (I_I):
- Maximum: ±1 µA at V_CC = 15V

6. Output Current (I_O):
- Maximum: ±25 mA

7. Propagation Delay (t_PD):
- Typically 10 ns at V_CC = 5V

8. Power Dissipation:
- Maximum: 1.0 mW (for V_CC = 5V)

9. Temperature Range:
- Military grade: -55°C to +125°C

10. Package Type:
- Available in a 14-pin dual in-line package (DIP) and surface-mount options.

## Features

- Schmitt-Trigger Inputs: The Schmitt-trigger design provides hysteresis, which improves noise immunity and allows for reliable operation with slow input signals.
- High Speed: The device is capable of fast switching speeds, making it suitable for high-frequency applications.
- Low Power Consumption: The 54S140FM is designed to operate with minimal power, making it ideal for battery-powered devices and energy-efficient applications.
- Wide Supply Voltage Range: The ability to operate over a broad voltage range enhances its versatility in various circuit designs.
- Robust Performance: Designed to meet military specifications, the device is built to withstand harsh environmental conditions.

## Applications

The National Semiconductor 54S140FM is suitable for a wide range of applications, including:

- Digital Signal Processing: Used in circuits that require clean signal transitions, such as in digital communication systems.
- Microcontroller Interfaces: Ideal for interfacing with microcontrollers where signal integrity is crucial.
- Timing Circuits: Can be used in timing applications where precise signal timing is necessary.
- Data Communication: Employed in data transmission systems to ensure reliable signal integrity over long distances.

## Conclusion

The National Semiconductor 54S140FM is a reliable and efficient hex Schmitt-trigger inverter that meets the demands of modern digital applications. With its fast switching capabilities, low power consumption, and robust performance in challenging environments, it is an excellent choice for engineers looking to enhance the reliability and efficiency of their designs. Its versatility and compliance with military specifications further solidify its position as a preferred component in critical applications.