SLVSFH8B September   2021  – March 2022 LM74720-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 Dual Gate Control (GATE, PD)
        1. 8.3.1.1 Reverse Battery Protection (A, C, GATE)
        2. 8.3.1.2 Load Disconnect Switch Control (PD)
      2. 8.3.2 Overvoltage Protection and Battery Voltage Sensing (VSNS, SW, OV)
      3. 8.3.3 Boost Regulator
    4. 8.4 Device Functional Mode (Shutdown Mode)
  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
        1. 9.2.2.1 Input Transient Protection: ISO 7637-2 Pulse 1
        2. 9.2.2.2 AC Super Imposed Input Rectification: ISO 16750-2 and LV124 E-06
        3. 9.2.2.3 Input Micro-Short Protection: LV124 E-10
      3. 9.2.3 Detailed Design Procedure
        1. 9.2.3.1 Design Considerations
        2. 9.2.3.2 Boost Converter Components (C2, C3, L1)
        3. 9.2.3.3 Input and Output Capacitance
        4. 9.2.3.4 Hold-Up Capacitance
        5. 9.2.3.5 Overvoltage Protection and Battery Monitor
        6. 9.2.3.6 MOSFET Selection: Blocking MOSFET Q1
        7. 9.2.3.7 MOSFET Selection: Load Disconnect MOSFET Q2
        8. 9.2.3.8 TVS Selection
      4. 9.2.4 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 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

Package Options

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

3 Description

The LM74720-Q1 ideal diode controller drives and controls external back-to-back N-Channel MOSFETs to emulate an ideal diode rectifier with power path ON/OFF control and overvoltage protection. The wide input supply of 3 V to 65 V allows protection and control of 12-V and 24-V automotive battery powered ECUs. The device can withstand and protect the loads from negative supply voltages down to –65 V. An integrated ideal diode controller (GATE) drives the first MOSFET to replace a Schottky diode for reverse input protection and output voltage holdup. A strong boost regulator with fast turn ON and OFF comparators ensures robust and efficient MOSFET switching performance during automotive testing such as ISO16750 or LV124 where an ECU is subjected to input short interruptions and AC superimpose input signals up to 100-kHz frequency. Low Quiescent Current 35 µA (maximum) in operation enables always ON system designs. With a second MOSFET in the power path, the device allows load disconnect control using EN pin. Quiescent current reduces to 3.3 μA (maximum) with EN low. The device features an adjustable overvoltage cut-off protection feature for load dump protection.

Device Information
PART NUMBERPACKAGE(1)BODY SIZE (NOM)
LM74720-Q1WSON (12)3.0 mm × 3.0 mm
(1) For all available packages, see the orderable addendum at the end of the data sheet.
GUID-20210831-SS0I-4VKW-ZRZZ-VQCCRHFCQNMH-low.gifLow IQ Ideal Diode
GUID-20210831-SS0I-14HM-MGXC-MXJNPXVN3CK0-low.gifLow IQ Ideal Diode with Switched Output