SBVS263B July   2017  – June 2025 TPS7A39

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Start-Up Characteristics
    7. 5.7 Timing Diagram
    8. 5.8 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Voltage Regulation
        1. 6.3.1.1 DC Regulation
        2. 6.3.1.2 AC and Transient Response
      2. 6.3.2 User-Settable Buffered Reference
      3. 6.3.3 Active Discharge
      4. 6.3.4 System Start-Up Controls
        1. 6.3.4.1 Start-Up Tracking
        2. 6.3.4.2 Sequencing
          1. 6.3.4.2.1 Enable (EN)
          2. 6.3.4.2.2 Undervoltage Lockout (UVLO) Control
    4. 6.4 Device Functional Modes
      1. 6.4.1 Normal Operation
      2. 6.4.2 Dropout Operation
      3. 6.4.3 Disabled
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1  Setting the Output Voltages on Adjustable Devices
      2. 7.1.2  Capacitor Recommendations
      3. 7.1.3  Input and Output Capacitor (CINx and COUTx)
      4. 7.1.4  Feed-Forward Capacitor (CFFx)
      5. 7.1.5  Noise-Reduction and Soft-Start Capacitor (CNR/SS)
      6. 7.1.6  Buffered Reference Voltage
      7. 7.1.7  Overriding Internal Reference
      8. 7.1.8  Start-Up
        1. 7.1.8.1 Soft-Start Control (NR/SS)
          1. 7.1.8.1.1 In-Rush Current
        2. 7.1.8.2 Undervoltage Lockout (UVLOx) Control
      9. 7.1.9  AC and Transient Performance
        1. 7.1.9.1 Power-Supply Rejection Ratio (PSRR)
        2. 7.1.9.2 Channel-to-Channel Output Isolation and Crosstalk
        3. 7.1.9.3 Output Voltage Noise
        4. 7.1.9.4 Optimizing Noise and PSRR
        5. 7.1.9.5 Load Transient Response
      10. 7.1.10 DC Performance
        1. 7.1.10.1 Output Voltage Accuracy (VOUT x)
        2. 7.1.10.2 Dropout Voltage (VDO)
      11. 7.1.11 Reverse Current
      12. 7.1.12 Power Dissipation (PD)
        1. 7.1.12.1 Estimating Junction Temperature
    2. 7.2 Typical Applications
      1. 7.2.1 Design 1: Single-Ended to Differential Isolated Supply
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
          1. 7.2.1.2.1 Switcher Choice
          2. 7.2.1.2.2 Full Bridge Rectifier With Center-Tapped Transformer
          3. 7.2.1.2.3 Total Solution Efficiency
          4. 7.2.1.2.4 Feedback Resistor Selection
        3. 7.2.1.3 Application Curves
      2. 7.2.2 Design 2: Getting the Full Range of a SAR ADC
        1. 7.2.2.1 Design Requirements
        2. 7.2.2.2 Detailed Design Procedure
        3. 7.2.2.3 Detailed Design Description
          1. 7.2.2.3.1 Regulation of –0.2V
          2. 7.2.2.3.2 Feedback Resistor Selection
        4. 7.2.2.4 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
        1. 7.4.1.1 Board Layout Recommendations to Improve PSRR and Noise Performance
        2. 7.4.1.2 Package Mounting
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Development Support
        1. 8.1.1.1 Evaluation Modules
        2. 8.1.1.2 Spice Models
    2. 8.2 Documentation Support
      1. 8.2.1 Related Documentation
    3. 8.3 Receiving Notification of Documentation Updates
    4. 8.4 Support Resources
    5. 8.5 Trademarks
    6. 8.6 Electrostatic Discharge Caution
    7. 8.7 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

7.1.7 Overriding Internal Reference

The internal reference of the LDO can be overridden using an external source to increase the accuracy of the LDO and lower the output noise. To override the internal reference connect the external source to the NR/SS pin of the LDO. To overdrive the internal reference the external source must be able to source or sink 100µA or greater.

The internal reference achieves a 2% accuracy from –40°C to +125°C; using an external reference can help achieve better accuracy over temperature.