TIDUFE2 October   2025

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Fault Detection and Protection
      2. 2.2.2 Theory of Operation - Parallel LDOs Using Op Amps
      3. 2.2.3 Theory of Operation - Parallel LDOs Using Ballast Resistors
    3. 2.3 Highlighted Products
      1. 2.3.1 TPS7B7702-Q1, Automotive, Dual-Channel Antenna Low Dropout (LDO) Regulator With Current Sense
      2. 2.3.2 OPAx388 Automotive, Precision, Zero-Drift, Zero-Crossover, True Rail-to-Rail, Input/Output Operational Amplifiers
      3. 2.3.3 LMV321A-Q1 Automotive Low-Voltage Rail-to-Rail Output Operational Amplifier
  9. 3Hardware, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Test Setup
    3. 3.3 Test Results - Parallel LDOs Using Op Amps
      1. 3.3.1 Short to Battery
      2. 3.3.2 Load Transient Response
      3. 3.3.3 Current Limit
      4. 3.3.4 Start-Up
      5. 3.3.5 Shutdown
      6. 3.3.6 Line Transient
      7. 3.3.7 PSRR
      8. 3.3.8 Thermal Performance
      9. 3.3.9 Thermal Limit Protection
    4. 3.4 Test Results - Parallel LDOs Using Ballast Resistors
      1. 3.4.1 Short to Battery
      2. 3.4.2 Load Transient Response
      3. 3.4.3 Current Limit
      4. 3.4.4 Start-Up
      5. 3.4.5 Line Transient
      6. 3.4.6 Thermal Performance
      7. 3.4.7 Thermal Limit Protection
    5. 3.5 Comparison of Results Between Parallel LDO Techniques
      1. 3.5.1 VLOAD vs ILOAD
      2. 3.5.2 PSRR
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
      3. 4.1.3 Layout Prints
    2. 4.2 Tools
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  11. 5About the Author

2.2 Design Considerations

This reference design showcases two different techniques to paralleling the TPS7B7702-Q1 channels. One technique uses operational amplifiers to parallel multiple LDO channels while the second technique uses ballast resistors to parallel the LDO channels. Details of these different techniques, and design considerations of these techniques are discussed in Section 2.2.2 and Section 2.2.3.