SLUSG31 November   2025 TPSM828502-Q1

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 Typical Characteristics
  8. 7 Parameter Measurement Information
    1. 7.1 Schematic
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Precise Enable (EN)
      2. 8.3.2 COMP/FSET
      3. 8.3.3 MODE/SYNC
      4. 8.3.4 Spread Spectrum Clocking (SSC)
      5. 8.3.5 Undervoltage Lockout (UVLO)
      6. 8.3.6 Power-Good Output (PG)
      7. 8.3.7 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Pulse Width Modulation (PWM) Operation
      2. 8.4.2 Power Save Mode Operation (PFM/PWM)
      3. 8.4.3 100% Duty-Cycle Operation
      4. 8.4.4 Current Limit and Short-Circuit Protection
      5. 8.4.5 Output Discharge
  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 Setting the Output Voltage
        2. 9.2.2.2 Feedforward Capacitor
        3. 9.2.2.3 Input Capacitor
        4. 9.2.2.4 Output Capacitor
      3. 9.2.3 Application Curves
    3. 9.3 System Examples
      1. 9.3.1 Synchronizing to an External Clock
    4. 9.4 Power Supply Recommendations
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
      2. 9.5.2 Layout Example
        1. 9.5.2.1 Thermal Consideration
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Third-Party Products Disclaimer
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 Receiving Notification of Documentation Updates
    4. 10.4 Support Resources
    5. 10.5 Trademarks
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

8.4.4 Current Limit and Short-Circuit Protection

The TPSM82850x-Q1 devices are protected against overload and short-circuit events. If the inductor current exceeds the current limit ILIMH, the high-side MOSFET is turned off and the low-side MOSFET is turned on to ramp down the inductor current. The high-side MOSFET turns on again only if the current in the low-side MOSFET has decreased below the low-side current limit. Due to internal propagation delays, the actual current can exceed the static current limit. The following equation gives the dynamic current limit:

Equation 2. Ipeak=ILIMH+VLL×tPD

where

  • ILIMH is the static current limit, as specified in the electrical characteristics
  • L is the effective inductance of the internal inductor (typical 0.47μH)
  • VL is the voltage across the inductor (VIN – VOUT)
  • tPD is the internal propagation delay of typically 50ns

The current limit can exceed static values, especially if the input voltage is high and very small inductances are used. Calculate the dynamic high-side switch peak current as follows:

Equation 3. Ipeak=ILIMH+VIN-VOUTL×50ns