SNOSDD8 December   2022 LM7480

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Switching Characteristics
    7. 7.7 Typical Characteristics
  8. 8 Parameter Measurement Information
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Charge Pump
      2. 9.3.2 Dual Gate Control (DGATE, HGATE)
        1. 9.3.2.1 Reverse Battery Protection (A, C, DGATE)
        2. 9.3.2.2 Load Disconnect Switch Control (HGATE, OUT)
      3. 9.3.3 Overvoltage Protection and Battery Voltage Sensing (VSNS, SW, OV)
      4. 9.3.4 Low Iq Shutdown and Under Voltage Lockout (EN/UVLO)
    4. 9.4 Device Functional Modes
    5. 9.5 Application Examples
      1. 9.5.1 Redundant Supply OR-ing with Inrush Current Limiting, Overvoltage Protection and ON/OFF Control
      2. 9.5.2 Ideal Diode With Unsuppressed Load Dump Protection
  10. 10Applications and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical 12-V Reverse Battery Protection Application
      1. 10.2.1 Design Requirements for 12-V Battery Protection
      2. 10.2.2 Automotive Reverse Battery Protection
      3. 10.2.3 Detailed Design Procedure
        1. 10.2.3.1 Design Considerations
        2. 10.2.3.2 Charge Pump Capacitance VCAP
        3. 10.2.3.3 Input and Output Capacitance
        4. 10.2.3.4 Hold-Up Capacitance
        5. 10.2.3.5 Overvoltage Protection and Battery Monitor
      4. 10.2.4 MOSFET Selection: Blocking MOSFET Q1
      5. 10.2.5 MOSFET Selection: Hot-Swap MOSFET Q2
      6. 10.2.6 TVS Selection
      7. 10.2.7 Application Curves
    3. 10.3 200-V Unsuppressed Load Dump Protection Application
      1. 10.3.1 Design Requirements for 200-V Unsuppressed Load Dump Protection
      2. 10.3.2 Design Procedure
        1. 10.3.2.1 Boost Converter Components (C2, C3, L1)
        2. 10.3.2.2 Input and Output Capacitance
        3. 10.3.2.3 VS Capacitance, Resistor, and Zener Clamp
        4. 10.3.2.4 Overvoltage Protection and Output Clamp
        5. 10.3.2.5 MOSFET Q1 Selection
        6. 10.3.2.6 Input TVS Selection
        7. 10.3.2.7 MOSFET Q2 Selection
      3. 10.3.3 Application Curves
    4. 10.4 Do's and Don'ts
    5. 10.5 Power Supply Recommendations
      1. 10.5.1 Transient Protection
      2. 10.5.2 TVS Selection for 12-V Battery Systems
      3. 10.5.3 TVS Selection for 24-V Battery Systems
    6. 10.6 Layout
      1. 10.6.1 Layout Guidelines
      2. 10.6.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Receiving Notification of Documentation Updates
    2. 11.2 Support Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

10.2.2 Automotive Reverse Battery Protection

The LM7480 feature two separate gate control and driver outputs i.e DGATE and HGATE to drive back to back N-channel MOSFETs. This enables LM7480 to provide comprehensive immunity with robust system protection during various automotive transient tests as per ISO 7637-2 and ISO 16750-2 standard as well as other automotive OEM standards. For more information, see the Automotive EMC-compliant reverse-battery protection with ideal-diode controllers article.

LM7480 gate drive output DGATE controls MOSFET Q1 to provide reverse battery protection and true reverse current blocking functionality. HGATE controls MOSFET Q2 to turn off the power path during input overvoltage condition. Resistor network R1, R2 and R3 connected to OV and SW can be configured for overvoltage protection and also for battery monitoring under normal operating conditions as well as reverse battery conditions. Bi-directional TVS D1 clamps the automotive transient input voltages on the 12-V battery, both positive and negative transients, to voltage levels safe for MOSFET Q1 and LM7480.

Fast reverse current blocking response and quick reverse recovery enables LM7480 to turn ON/OFF MOSFET Q1 during AC super imposed input and provide active rectification of the AC input superimposed on DC battery voltage. Fast reverse current blocking response of LM7480 helps to turn off MOSFET Q1 during negative transients inputs and input micro short interruption conditions where input can fall to 0-V for short duration.