SNOSDC2B September   2021  – July 2022 LM74721-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 Reverse Battery Protection (A, C, GATE)
        1. 8.3.1.1 Input TVS Less Operation: VDS Clamp
      2. 8.3.2 Load Disconnect Switch Control (PD)
      3. 8.3.3 Overvoltage Protection and Battery Voltage Sensing (VSNS, SW, OV)
      4. 8.3.4 Boost Regulator
    4. 8.4 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 Detailed Design Procedure
        1. 9.2.2.1 Boost Converter Components (C2, C3, L1)
        2. 9.2.2.2 Input and Output Capacitance
        3. 9.2.2.3 Hold-Up Capacitance
        4. 9.2.2.4 MOSFET Selection: Q1
      3. 9.2.3 Application Curves
    3. 9.3 What to Do and What Not to Do
  10. 10Power Supply Recommendations
    1. 10.1 Transient Protection
  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

Package Options

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

3 Description

The LM74721-Q1 ideal diode controller drives and controls external back to back N-Channel MOSFETs to emulate an ideal diode rectifier with power path ON and OFF control and overvoltage protection. The wide input supply of 3 V to 65 V allows protection and control of 12-V automotive battery powered ECUs. The device can withstand and protect the loads from negative supply voltages down to –33-V DC. An integrated ideal diode controller (GATE) drives the first MOSFET to replace a Schottky diode for reverse input protection and output voltage holdup. Integrated VDS clamp feature enables input TVS less system designs for automotive ISO7637 pulse suppression. 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 cutoff protection feature for load dump protection.

Device Information
PART NUMBERPACKAGE(1)BODY SIZE (NOM)
LM74721-Q1WSON (12)3.00 mm × 3.00 mm
(1) For all available packages, see the orderable addendum at the end of the data sheet.
GUID-20210428-CA0I-WBBD-ZNS5-67B4GLF3NQDR-low.gifLow IQ TVS Less Ideal Diode for 12-V Battery Powered Automotive Applications
GUID-20210906-SS0I-4TRV-RL1D-3N2D1LBPHGSM-low.gifTVS Less ISO7637-2 Pulse 1 Performance