SNOSD98A May   2020  – December 2020 LM7481-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 Charge Pump
      2. 8.3.2 Dual Gate Control (DGATE, HGATE)
        1. 8.3.2.1 Reverse Battery Protection (A, C, DGATE)
        2. 8.3.2.2 Load Disconnect Switch Control (HGATE, OUT)
      3. 8.3.3 Over Voltage Protection and Battery Voltage sensing (VSNS, SW, OV)
      4. 8.3.4 Low Iq Shutdown and Under Voltage Lockout (EN/UVLO)
    4. 8.4 Device Functional Modes
    5. 8.5 Application Examples
      1. 8.5.1 Redundant Supply OR-ing with Inrush Current Limiting, Over Voltage Protection and ON/OFF Control
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical 12-V Reverse Battery Protection Application
      1. 9.2.1  Design Requirements for 12-V Battery Protection
      2. 9.2.2  Automotive Reverse Battery Protection
      3. 9.2.3  Input Transient Protection: ISO 7637-2 Pulse 1
      4. 9.2.4  AC Super Imposed Input Rectification: ISO 16750-2 and LV124 E-06
      5. 9.2.5  Input Micro-Short Protection: LV124 E-10
      6. 9.2.6  Detailed Design Procedure
        1. 9.2.6.1 Design Considerations
        2. 9.2.6.2 Charge Pump Capacitance VCAP
        3. 9.2.6.3 Input and Output Capacitance
        4. 9.2.6.4 Hold-up Capacitance
        5. 9.2.6.5 Over Voltage Protection and Battery Monitor
      7. 9.2.7  MOSFET Selection: Blocking MOSFET Q1
      8. 9.2.8  MOSFET Selection: Hot-Swap MOSFET Q2
      9. 9.2.9  TVS selection
      10. 9.2.10 Application Curves
    3. 9.3 Do's and Don'ts
  10. 10Power Supply Recommendations
    1. 10.1 Transient Protection
    2. 10.2 TVS Selection for 12-V Battery Systems
    3. 10.3 TVS Selection for 24-V Battery Systems
  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

5 Pin Configuration and Functions

GUID-D3C13CA3-EC89-46F5-8E03-8136201E3CDE-low.gifFigure 5-1 12-Pin WSONTop View
Table 5-1 Pin Functions
PINTYPEDESCRIPTION
NAMELM74810-Q1
WSON
DGATE1ODiode Controller Gate Drive Output. Connect to the GATE of the external MOSFET. Anode of the ideal diode.
A2IAnode of the ideal diode. Connect to the source of the external MOSFET
VSNS3IVoltage sensing input.
SW4IVoltage sensing disconnect switch terminal. VSNS and SW are internally connected through a switch. Use SW as the top connection of the battery sensing or OV resistor ladder network. When EN/UVLO is pulled low, the switch is OFF disconnecting the resistor ladder from the battery line thereby cutting off the leakage current. If the internal disconnect switch between VSNS and SW is not used then short them together and connect to VS pin.
OV5IAdjustable over voltage threshold input. Connect a resistor ladder across SW to OV terminal. When the voltage at OVP exceeds the over voltage cut-off threshold then the HGATE is pulled low turning OFF the HSFET. HGATE turns ON when the sense voltage goes below the OVP falling threshold.
EN/UVLO6IEN/UVLO Input. Connect to VS pin for always ON operation. Can be driven externally from a mirco controller I/O. Pulling it low below V(ENF) makes the device enter into low Iq shutdown mode. For UVLO, connect an external resistor ladder to EN/UVLO to GND.
GND7GConnect to the system ground plane.
HGATE8OGATE driver output for the HSFET. Connect to the GATE of the external FET
OUT9IConnect to the output rail (external MOSFET source).
VS10IInput power supply to the IC. Connect VS to middle point of the common drain back to back MOSFET configuration. Connect a 100nF capacitor across VS and GND pins.
CAP11OCharge pump output. Connect a 100-nF capacitor across CAP and VS pins.
C12ICathode of the ideal diode. Connect to the drain of the external MOSFET
RTNThermal Pad—Leave exposed pad floating. Do not connect to GND plane.