SNOSD87A July   2021  – February 2022 LM74501-Q1

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
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Switching Characteristics
    7. 6.7 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 Input Voltage
      2. 8.3.2 Charge Pump
      3. 8.3.3 Enable
      4. 8.3.4 Gate Driver
      5. 8.3.5 SW (Battery Voltage Monitoring)
      6. 8.3.6 Gate Discharge Timer
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Full Conduction Mode
      3. 8.4.3 VDS Clamp
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Reverse Battery Protection
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Design Considerations
        2. 9.2.2.2 MOSFET Selection
        3. 9.2.2.3 Gate Discharge Timer Capacitor Selection (CT)
        4. 9.2.2.4 Charge Pump VCAP, Input and Output Capacitance
      3. 9.2.3 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 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

8.4.3 VDS Clamp

The LM74501-Q1 has an integrated VDS clamp feature that turns on an external MOSFET whenever voltage difference between DRIAN and SOURCE exceeds VDS clamp threshold (20 V typical) when enable pin is pulled low. This use case scenario is specially true when the LM74501-Q1 is used to drive inductive loads and overshoot can happen at the DRAIN pin due to regenerative action of the motor load. Also, if the gate discharge timer designed to keep external MOSFET on during an ISO7637-2 pulse 1 event expires within stipulated time window due to component level tolerances, the LM74501-Q1 VDS clamp feature provides second level of protection to keep maximum voltage across FET to 20 V.