SLVSC55D August   2013  – June 2025 TPS62090-Q1

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 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  Enable and Disable (EN)
      2. 6.3.2  Soft Start (SS) and Hiccup Current Limit During Start-Up
      3. 6.3.3  Voltage Tracking (SS)
      4. 6.3.4  Short-Circuit Protection (Hiccup Mode)
      5. 6.3.5  Output Discharge Function
      6. 6.3.6  Power Good Output (PG)
      7. 6.3.7  Frequency Set Pin (FREQ)
      8. 6.3.8  Undervoltage Lockout (UVLO)
      9. 6.3.9  Thermal Shutdown
      10. 6.3.10 Charge Pump (CP, CN)
    4. 6.4 Device Functional Modes
      1. 6.4.1 Pulse Width Modulation Operation
      2. 6.4.2 Power Save Mode Operation
      3. 6.4.3 Low-Dropout Operation (100% Duty Cycle)
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Inductor Selection
        2. 7.2.2.2 Input and Output Capacitor Selection
        3. 7.2.2.3 Setting the Output Voltage
      3. 7.2.3 Application Curves
    3. 7.3 System Examples
    4. 7.4 Power Supply Recommendations
    5. 7.5 Layout
      1. 7.5.1 Layout Guidelines
      2. 7.5.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Third-Party Products Disclaimer
    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

6.3.3 Voltage Tracking (SS)

The SS pin is externally driven by another voltage source to achieve output voltage tracking. The application circuit is shown in Figure 6-1. The internal reference voltage follows the voltage at the SS pin with a fraction of 1.56 until the internal reference voltage of 0.8 V is reached. The device achieves ratiometric or coincidental (simultaneous) output tracking, as shown in Figure 6-2.

TPS62090-Q1 Output Voltage TrackingFigure 6-1 Output Voltage Tracking
TPS62090-Q1 Voltage Tracking OptionsFigure 6-2 Voltage Tracking Options

The R2 value must be set properly to achieve accurate voltage tracking by taking 7.5-µA soft start-up current into account. 1 kΩ or smaller is a sufficient value for R2.

For decreasing the SS pin voltage, the device does not sink current from the output when the device is in power save mode. So the resulting decreases of the output voltage can be slower than the SS pin voltage if the load is light. When driving the SS pin with an external voltage, do not exceed the voltage rating of the SS pin which is
7 V.