ON Semiconductor
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MM74HCT138N
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MM74HCT138N

Product Overview

  • Category: Integrated Circuit (IC)
  • Use: Decoder/Demultiplexer
  • Characteristics: High-Speed CMOS Logic, 3-to-8 Line Decoder
  • Package: DIP (Dual In-line Package)
  • Essence: Converts a binary input into a corresponding output line
  • Packaging/Quantity: Available in tubes of 25 units or reels of 2,000 units

Specifications

  • Supply Voltage Range: 4.5V to 5.5V
  • Input Voltage Range: 0V to VCC
  • Output Voltage Range: 0V to VCC
  • Maximum Operating Frequency: 25 MHz
  • Number of Inputs: 3
  • Number of Outputs: 8
  • Propagation Delay Time: 15 ns (typical)

Detailed Pin Configuration

The MM74HCT138N has a total of 16 pins, which are assigned as follows:

  1. GND (Ground)
  2. A0 (Input A0)
  3. A1 (Input A1)
  4. A2 (Input A2)
  5. E1 (Enable Input 1)
  6. Y0 (Output Y0)
  7. Y1 (Output Y1)
  8. Y2 (Output Y2)
  9. Y3 (Output Y3)
  10. Y4 (Output Y4)
  11. Y5 (Output Y5)
  12. Y6 (Output Y6)
  13. Y7 (Output Y7)
  14. E2 (Enable Input 2)
  15. VCC (Positive Power Supply)
  16. GND (Ground)

Functional Features

  • Converts a 3-bit binary input into one of the eight corresponding output lines
  • Enables easy selection of specific output lines based on the input combination
  • High-speed operation allows for efficient decoding in various applications
  • CMOS logic ensures low power consumption and compatibility with TTL inputs

Advantages and Disadvantages

Advantages: - Compact and versatile decoder/demultiplexer IC - High-speed operation for efficient decoding - Low power consumption due to CMOS technology - Easy selection of specific output lines based on input combination

Disadvantages: - Limited to 3-bit binary input, restricting the number of possible combinations - Propagation delay may affect timing-sensitive applications

Working Principles

The MM74HCT138N operates by receiving a 3-bit binary input (A0, A1, A2) and converting it into one of the eight corresponding output lines (Y0-Y7). The enable inputs (E1 and E2) control the functionality of the decoder. When both enable inputs are active (low), the decoder is enabled, and the selected output line reflects the binary input combination.

Detailed Application Field Plans

The MM74HCT138N finds applications in various fields, including:

  1. Address Decoding: Used in microcontrollers and memory systems to select specific addresses.
  2. Data Demultiplexing: Enables the distribution of data from a single source to multiple destinations.
  3. Digital Displays: Controls the activation of specific segments in multiplexed displays.
  4. Programmable Logic Controllers (PLCs): Facilitates input/output selection and control signal routing.

Detailed and Complete Alternative Models

  1. 74HC138: Similar 3-to-8 line decoder/demultiplexer IC with slightly different electrical characteristics.
  2. CD74HCT138: Another 3-to-8 line decoder/demultiplexer IC with similar functionality but different package options.
  3. SN74HCT138: Texas Instruments' version of the 3-to-8 line decoder/demultiplexer IC.

(Note: This list is not exhaustive and other alternative models may exist.)

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Énumérez 10 questions et réponses courantes liées à l'application de MM74HCT138N dans les solutions techniques

Sure! Here are 10 common questions and answers related to the application of MM74HCT138N in technical solutions:

  1. Q: What is MM74HCT138N? A: MM74HCT138N is a 3-to-8 line decoder/demultiplexer integrated circuit (IC) that converts binary information from three input lines into eight output lines.

  2. Q: What is the purpose of using MM74HCT138N in a technical solution? A: MM74HCT138N is commonly used to expand the number of output lines available from a microcontroller or other digital device, allowing for more complex control and addressing schemes.

  3. Q: How does MM74HCT138N work? A: The IC uses three input lines (A0, A1, and A2) to select one of the eight output lines (Y0-Y7) based on the binary input combination.

  4. Q: What is the maximum input voltage for MM74HCT138N? A: The maximum input voltage for MM74HCT138N is typically 5.5V.

  5. Q: Can MM74HCT138N handle high-speed signals? A: Yes, MM74HCT138N is designed to operate at high speeds, making it suitable for applications requiring fast switching times.

  6. Q: Is MM74HCT138N compatible with both TTL and CMOS logic levels? A: Yes, MM74HCT138N is compatible with both TTL and CMOS logic levels, making it versatile for use with various digital devices.

  7. Q: Can MM74HCT138N be cascaded to increase the number of output lines? A: Yes, multiple MM74HCT138N ICs can be cascaded together to expand the number of output lines beyond eight.

  8. Q: What is the power supply voltage range for MM74HCT138N? A: The power supply voltage range for MM74HCT138N is typically between 2V and 6V.

  9. Q: Does MM74HCT138N have any built-in protection features? A: Yes, MM74HCT138N has built-in diode clamps on all inputs to protect against electrostatic discharge (ESD) damage.

  10. Q: Are there any specific precautions to consider when using MM74HCT138N? A: It is important to ensure that the input voltage levels are within the specified range and to avoid exceeding the maximum ratings to prevent damage to the IC. Additionally, proper decoupling capacitors should be used to stabilize the power supply.