SNOU187 September   2021

 

  1.   Trademarks
  2. 1Introduction
    1. 1.1 Features
    2. 1.2 Applications
  3. 2Description
    1. 2.1 Input Power and Load (J2, J6 and J3, J7):
    2. 2.2 Enable Control (J5):
    3. 2.3 Two Back-to-Back Connected MOSFETs (Q1 and Q2):
    4. 2.4 Output Slew Rate Control (R5 and C5):
    5. 2.5 Output Schottky Diode (D3) and LED Indication:
    6. 2.6 TVS Selection for 12-V Battery Protection:
    7. 2.7 Test Points:
  4. 3Schematic
  5. 4Test Equipment Requirements
    1. 4.1 Power Supplies
    2. 4.2 Meters
    3. 4.3 Oscilloscope
    4. 4.4 Loads
  6. 5Test Setup and Results
    1. 5.1 Initial Setup
    2. 5.2 Power Up
    3. 5.3 Enable Control
    4. 5.4 Hot-Plug and Disable Using EN
    5. 5.5 Inrush Current Control
    6. 5.6 Load Response
  7. 6Board Layout and Bill of Materials
    1. 6.1 Board Layout
    2. 6.2 Bill of Materials

2.6 TVS Selection for 12-V Battery Protection:

By default, the TVS diode D2 at the input is not populated as the LM74721-Q1 enables input TVS less system designs for automotive ISO7637-2 pulse 1 suppression. A suitable TVS can be populated in case voltage transients beyond the absolute maximum rating of the device can occur on the positive side in the system.