SNOSDE6B december   2022  – july 2023 LM74900-Q1 , LM74910-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Device Comparison Table
  7. 6 Pin Configuration and Functions
  8. 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
  9. 8 Parameter Measurement Information
  10. 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 Overcurrent Protection (CS+, CS-, ILIM, IMON, TMR)
        1. 9.3.3.1 Pulse Overload Protection, Circuit Breaker
        2. 9.3.3.2 Overcurrent Protection With Latch-Off
        3. 9.3.3.3 Short Circuit Protection (ISCP)
        4. 9.3.3.4 Analog Current Monitor Output (IMON)
      4. 9.3.4 Undervoltage Protection, Overvoltage Protection, and Battery Voltage Sensing (UVLO, OV, SW)
      5. 9.3.5 Low IQ SLEEP Mode (SLEEP)
      6. 9.3.6 Ultra Low IQ Shutdown (EN)
  11. 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
        1. 10.2.2.1 Input Transient Protection: ISO 7637-2 Pulse 1
        2. 10.2.2.2 AC Super Imposed Input Rectification: ISO 16750-2 and LV124 E-06
        3. 10.2.2.3 Input Micro-Short Protection: LV124 E-10
      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 Selection of Current Sense Resistor, RSNS
        6. 10.2.3.6 Selection of Scaling Resistor (RSET) and Short-Circuit Protection Setting Resistor (RSCP)
        7. 10.2.3.7 Overcurrent Limit (ILIM), Circuit Breaker Timer (TMR), and Current Monitoring Output (IMON) Selection
        8. 10.2.3.8 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 Addressing Automotive Input Reverse Battery Protection Topologies With LM749x0-Q1
    4. 10.4 Power Supply Recommendations
      1. 10.4.1 Transient Protection
      2. 10.4.2 TVS Selection for 12-V Battery Systems
    5. 10.5 Layout
      1. 10.5.1 Layout Guidelines
  12. 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
  13. 12Mechanical, Packaging, and Orderable Information

Package Options

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

10.2.3.1 Design Considerations

Table 10-1 summarizes the design parameters that must be known for designing an automotive reverse battery protection circuit with overvoltage cut-off. During power up, inrush current through MOSFET Q2 needs to be limited so that the MOSFET operates well within its SOA. Maximum load current, maximum ambient temperature and thermal properties of the PCB determine the RDSON of the MOSFET Q2 and maximum operating voltage determines the voltage rating of the MOSFET Q2. Selection of MOSFET Q1 is determined mainly by the maximum operating load current, maximum ambient temperature, maximum frequency of AC super imposed voltage ripple and ISO 7637-2 pulse 1 requirements. overvoltage threshold is decided based on the rating of downstream DC/DC converter or other components after the reverse battery protection circuit. A single bi-directional TVS or two back-back uni-directional TVS are required to clamp input transients to a safe operating level for the MOSFETs Q1, Q2 and LM749x0-Q1.