SLVSII7 December   2025 TPSM8D7420 , TPSM8D7620

PRODUCTION DATA  

  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 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Input Voltage Range (VIN)
      2. 7.3.2  Bias Supply Regulator (VCC)
      3. 7.3.3  Device Configuration Pin (MSEL)
      4. 7.3.4  Multiphase Output Configuration
      5. 7.3.5  Enable and Adjustable UVLO
      6. 7.3.6  Adjustable Switching Frequency
      7. 7.3.7  Device Synchronization (SYNC)
        1. 7.3.7.1 Clock Locking
      8. 7.3.8  Adjustable Output Voltage (FB)
      9. 7.3.9  Control Loop Compensation (COMP)
      10. 7.3.10 Slope Compensation
      11. 7.3.11 Power-Good Output Voltage Monitoring
      12. 7.3.12 Output Discharge
      13. 7.3.13 Soft-Start (SS)
      14. 7.3.14 Overcurrent Protection (OCP)
      15. 7.3.15 Temperature Output
      16. 7.3.16 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Standby Mode
      3. 7.4.3 Active Mode
        1. 7.4.3.1 Peak Current Mode Operation
        2. 7.4.3.2 Diode Emulation
        3. 7.4.3.3 FPWM Mode Operation
        4. 7.4.3.4 Minimum On-time (High Input Voltage) Operation
        5. 7.4.3.5 Dropout
        6. 7.4.3.6 Recovery from Dropout
  9. 8 Applications and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Custom Design With WEBENCH® Tools
        2. 8.2.2.2 Choosing the Switching Frequency
        3. 8.2.2.3 Setting the Output Voltage
        4. 8.2.2.4 Integrated Inductor Considerations
        5. 8.2.2.5 Input Capacitor Selection
        6. 8.2.2.6 VCC and BOOT Capacitors
        7. 8.2.2.7 Output Capacitor Selection
        8. 8.2.2.8 Compensation Selection
      3. 8.2.3 Application Curves
    3. 8.3 2-PH Application
      1. 8.3.1 Design Requirements
      2. 8.3.2 Detailed Design Procedure
      3. 8.3.3 Application Curves 2-PH
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
        1. 8.5.1.1 Thermal Design and Layout
      2. 8.5.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Third-Party Products Disclaimer
      2. 9.1.2 Development Support
        1. 9.1.2.1 Custom Design With WEBENCH® Tools
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

8.4 Power Supply Recommendations

The TPSM8D7x20 buck module is designed to operate over a wide input voltage range of 4V to 17V. The characteristics of the input supply must be compatible with the Absolute Maximum Ratings and Recommended Operating Conditions in this data sheet. In addition, the input supply must be capable of delivering the required input current to the loaded regulator circuit. Estimate the average input current with Equation 18.

Equation 18. IIN=VOUT×IOUTVIN×η

where

  • η is the efficiency.

If the module is connected to an input supply through long wires or PCB traces with a large impedance, take special care to achieve stable performance. The parasitic inductance and resistance of the input cables can have an adverse affect on module operation. More specifically, the parasitic inductance in combination with the low-ESR ceramic input capacitors form an under-damped resonant circuit, possibly resulting in instability or voltage transients each time the input supply is cycled ON and OFF. The parasitic resistance causes the input voltage to dip during a load transient. If the module is operating close to the minimum input voltage, this dip can cause false UVLO triggering and a system reset.

The best method to solve such issues is to reduce the distance from the input supply to the module and use an electrolytic input capacitor in parallel with the ceramics. The moderate ESR of the electrolytic capacitor helps damp the input resonant circuit and reduce any overshoot or undershoot at the input. A capacitance in the range of 47μF to 100μF is typically sufficient to provide input parallel damping and helps hold the input voltage steady during large load transients. A typical ESR of 0.1Ω to 0.4Ω provides enough damping for most input circuit configurations.