SCLS595B November   2004  – August 2024 CD74HC4538-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Description
  4. 3 Pin Configuration and Functions
  5. 4 Specifications
    1. 4.1 Absolute Maximum Ratings
    2. 4.2 ESD Ratings
    3. 4.3 Recommended Operating Conditions
    4. 4.4 Thermal Information
    5. 4.5 Electrical Characteristics
    6. 4.6 Timing Requirements
    7. 4.7 Switching Characteristics
    8. 4.8 Operating Characteristics
    9. 4.9 Typical Characteristics
  6. 5 Parameter Measurement Information
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Device Functional Modes
  8. 7 Application and Implementation
    1. 7.1 Typical Application
    2. 7.2 Power Supply Recommendations
    3. 7.3 Layout
      1. 7.3.1 Layout Guidelines
  9. 8 Device and Documentation Support
    1. 8.1 Documentation Support (Analog)
      1. 8.1.1 Related Links
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • PW|16
  • D|16
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.1 Typical Application

Power-Down Mode

During a rapid power-down condition (as would occur with a power-supply short circuit with a poorly filtered power supply), the energy stored in CX could discharge into pin 2 or pin 14. To avoid possible device damage in this mode when CX is \u0001 0.5 µF, a protection diode with a 1-A rating or higher (1N5395 or equivalent) and a separate ground return for CX should be provided. Rapid-Power-Down Protection Circuit

An alternate protection method is shown in Alternative Rapid-Power-Down Protection Circuit, where a 51-Ω current-limiting resistor is inserted in series with CX . Note that a small pulse-duration decrease occurs, however, and RX must be increased appropriately to obtain the originally desired pulse duration.

CD74HC4538-Q1 Rapid-Power-Down Protection CircuitFigure 7-1 Rapid-Power-Down Protection Circuit
CD74HC4538-Q1 Alternative Rapid-Power-Down Protection CircuitFigure 7-2 Alternative Rapid-Power-Down Protection Circuit