SNOSDB8A June   2021  – December 2021 LM74701-Q1

PRODUCTION DATA  

  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Pin Configuration and Functions
  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. Parameter Measurement Information
  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 Gate Driver
      4. 8.3.4 Enable
      5. 8.3.5 Battery Voltage Monitoring (SW)
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Conduction Mode
        1. 8.4.2.1 Regulated Conduction Mode
        2. 8.4.2.2 Full Conduction Mode
        3. 8.4.2.3 VDS Clamp Mode
      3. 8.4.3 Reverse Current Protection Mode
  9. Application and Implementation
    1. 9.1 Application Information
    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 Charge Pump VCAP (CVCAP) and Input Capacitance (CIN)
        4. 9.2.2.4 Output Capacitance (COUT)
      3. 9.2.3 Application Curves
    3. 9.3 What to Do and What Not to Do
    4. 9.4 OR-ing Application Configuration
  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

Overview

The LM74701-Q1 ideal diode controller has all the features necessary to implement an efficient and fast reverse polarity protection circuit while minimizing the number of external components. This easy to use ideal diode controller is paired with an external N-channel MOSFET to replace other reverse polarity schemes such as a P-channel MOSFET or a Schottky diode. An internal charge pump is used to drive the external N-Channel MOSFET to a maximum gate drive voltage of approximately 12 V. The voltage drop across the MOSFET is continuously monitored between the ANODE and CATHODE pins, and the GATE to ANODE voltage is adjusted as needed to regulate the forward voltage drop at 20 mV. This closed loop regulation scheme enables graceful turn off of the MOSFET during a reverse current event and ensures zero DC reverse current flow. A fast reverse current condition is detected when the voltage across ANODE and CATHODE pins reduces below –11 mV, resulting in the GATE pin being internally connected to the ANODE pin turning off the external N-channel MOSFET, and using the body diode to block any of the reverse current. An enable pin, EN is available to place the LM74701-Q1 in shutdown mode disabling the N-Channel MOSFET and minimizing the quiescent current. When device is enabled, an internal switch between SW and ANODE pin enables input voltage monitoring using an external resistor divider connected to SW pin. The device integrates VDS clamp feature which enables input TVS less reverse polarity protection. For additional details on achieving input TVS less reverse polarity protection solution, refer to the Device Functional Modes and Application Information section.