SCLS885 December   2022

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Recommended Operating Conditions (1)
    4. 6.4  Thermal Information
    5. 6.5  Electrical Characteristics
    6. 6.6  Switching Characteristics - VCC = 2.5 V ± 0.25 V
    7. 6.7  Switching Characteristics - VCC = 3.3 V ± 0.3 V
    8. 6.8  Switching Characteristics - VCC = 5 V ± 0.5 V
    9. 6.9  Operating Characteristics
    10. 6.10 Typical Characteristics
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Standard CMOS Inputs
      2. 8.3.2 Balanced CMOS Push-Pull Outputs
      3. 8.3.3 Partial Power Down (Ioff)
      4. 8.3.4 Wettable Flanks
      5. 8.3.5 Clamp Diode Structure
    4. 8.4 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Power Considerations
      2. 9.2.2 Input Considerations
      3. 9.2.3 Output Considerations
      4. 9.2.4 Detailed Design Procedure
      5. 9.2.5 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Support Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9.2.2 Input Considerations

Input signals must cross VIL(max) to be considered a logic LOW, and VIH(min) to be considered a logic HIGH. Do not exceed the maximum input voltage range found in the Absolute Maximum Ratings.

Unused inputs must be terminated to either VCC or ground. The unused inputs can be directly terminated if the input is completely unused, or they can be connected with a pull-up or pull-down resistor if the input will be used sometimes, but not always. A pull-up resistor is used for a default state of HIGH, and a pull-down resistor is used for a default state of LOW. The drive current of the controller, leakage current into the SN74LV138A-Q1 (as specified in the Electrical Characteristics), and the desired input transition rate limits the resistor size. A 10-kΩ resistor value is often used due to these factors.

The SN74LV138A-Q1 has CMOS inputs and thus requires fast input transitions to operate correctly, as defined in the Recommended Operating Conditions table. Slow input transitions can cause oscillations, additional power consumption, and reduction in device reliability.

Refer to the Feature Description section for additional information regarding the inputs for this device.