SLVSH61C March   2025  – November 2025 TPS7H4102-SEP , TPS7H4104-SEP

PRODMIX  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 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 Quality Conformance Inspection
    7. 6.7 Typical Characteristics
  8. 7 Parameter Measurement Information
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 VIN and Power VIN Pins (VIN and PVIN)
      2. 8.3.2 Voltage Reference
      3. 8.3.3 Setting VOUTx
        1. 8.3.3.1 VOUTx with Error
        2. 8.3.3.2 Minimum Output Voltage
        3. 8.3.3.3 Maximum Output Voltage
      4. 8.3.4 Enable and EN_SEQ
        1. 8.3.4.1 ENx and External UVLO
        2. 8.3.4.2 Sequence UP/DOWN (EN_SEQ)
      5. 8.3.5 Power Good (PWRGDx)
      6. 8.3.6 Adjustable Switching Frequency, Synchronization (SYNC) and Relative Phase Shift
        1. 8.3.6.1 Internal Clock Mode
        2. 8.3.6.2 External Clock Mode and Switchover
        3. 8.3.6.3 Relative Phase Shift
      7. 8.3.7 Turn-On Behavior
        1. 8.3.7.1 Pulse Skipping During Start-up
        2. 8.3.7.2 Soft-Start (SS_TRx)
        3. 8.3.7.3 Safe Start-up Into Pre-biased Outputs
        4. 8.3.7.4 Tracking and Sequencing (SS_TRx)
      8. 8.3.8 Protection Modes
        1. 8.3.8.1 Overcurrent Protection
          1. 8.3.8.1.1 High-Side Cycle by Cycle Overcurrent Protection (IOC_HSx)
          2. 8.3.8.1.2 Low-Side Sourcing Overcurrent Protection (IOC_LS_SOURCINGx)
          3. 8.3.8.1.3 COMPx Clamp Shutdown (COMPxCLAMP)
          4. 8.3.8.1.4 Low-Side Overcurrent Sourcing and Sinking Protection
        2. 8.3.8.2 Output Overvoltage Protection (OVP)
        3. 8.3.8.3 Thermal Shutdown
      9. 8.3.9 Error Amplifier and Loop Response
        1. 8.3.9.1 Error Amplifier
        2. 8.3.9.2 Power Stage Transconductance
        3. 8.3.9.3 Slope Compensation
        4. 8.3.9.4 Frequency Compensation
    4. 8.4 Device Functional Modes
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Operating Frequency
        2. 9.2.2.2 Output Inductor Selection
        3. 9.2.2.3 Output Capacitor Selection
        4. 9.2.2.4 Input Capacitor Selection
        5. 9.2.2.5 Soft-Start Capacitor Selection
        6. 9.2.2.6 Undervoltage Lockout (UVLO) Set Point
        7. 9.2.2.7 Output Voltage Feedback Resistor Selection
        8. 9.2.2.8 Slope Compensation Requirements
        9. 9.2.2.9 Compensation Component Selection
      3. 9.2.3 Application Curves
    3. 9.3 Parallel Operation
      1. 9.3.1 Input and Output Capacitance Reduction
        1. 9.3.1.1 Output Capacitance Reduction
        2. 9.3.1.2 Input Capacitance Reduction
    4. 9.4 Termination Guidelines for Unused Channels
    5. 9.5 Power Supply Recommendations
    6. 9.6 Layout
      1. 9.6.1 Layout Guidelines
      2. 9.6.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

9.2.2.5 Soft-Start Capacitor Selection

The soft-start capacitor CSS_TRx, determines the amount of time for the output voltage to reach nominal programmed value during power up. This is useful if a load requires a controlled voltage slew rate. This is also used if the output capacitance is large (as is typical with space grade buck converters), which requires a large amount of current to quickly charge the capacitor to the output voltage level. The large currents necessary to charge the capacitor can make the TPS7H410x reach the current limit, draw excessive current from the input power supply, or cause the input voltage rail to sag. Limiting the output voltage slew rate solves these problems. The soft-start capacitor value can be calculated using Equation 19 and Equation 20. The calculated value are shown in Table 9-7, along with the selected values. The center across temperature and voltage was used for VREFx and ISS_TRx for the calculations as: Equation 21, Equation 21, respectively.

Table 9-7 Soft-Start Capacitor Design Calculations
VOUTx (V) tSS_TRx_NOMINAL (ms) CSS_TRx_NOMINAL (nF) CSS_TRx_SELECTED (nF)
0.8 0.31 1.11 1.2
1.2 0.47 1.66 1.8
1.5 0.59 2.08 2.2
1.8 0.71 2.5 2.7