SLUSFE1 august   2023 TPSM843A22E

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  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  VIN Pins and VIN UVLO
      2. 7.3.2  Internal Bypassing (BP5)
      3. 7.3.3  Enable and Adjustable UVLO
        1. 7.3.3.1 Internal Sequence of Events During Start-up
      4. 7.3.4  Switching Frequency Selection
      5. 7.3.5  Switching Frequency Synchronization to an External Clock
        1. 7.3.5.1 Internal PWM Oscillator Frequency
        2. 7.3.5.2 Loss of Synchronization
        3. 7.3.5.3 Interfacing the SYNC/FSEL Pin
      6. 7.3.6  Remote Sense Amplifier and Adjusting the Output Voltage
      7. 7.3.7  Loop Compensation Guidelines
        1. 7.3.7.1 Output Filter Inductor Tradeoffs
        2. 7.3.7.2 Ramp Capacitor Selection
        3. 7.3.7.3 Output Capacitor Selection
        4. 7.3.7.4 Design Method for Good Transient Response
      8. 7.3.8  Soft Start and Prebiased Output Start-up
      9. 7.3.9  MSEL Pin
      10. 7.3.10 Power Good (PG)
      11. 7.3.11 Output Overload Protection
        1. 7.3.11.1 Positive Inductor Current Protection
        2. 7.3.11.2 Negative Inductor Current Protection
      12. 7.3.12 Output Overvoltage and Undervoltage Protection
      13. 7.3.13 Overtemperature Protection
      14. 7.3.14 Output Voltage Discharge
    4. 7.4 Device Functional Modes
      1. 7.4.1 Forced Continuous-Conduction Mode
      2. 7.4.2 Discontinuous Conduction Mode During Soft Start
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 1.0-V Output, 1-MHz Application
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1  Switching Frequency
          2. 8.2.1.2.2  Output Inductor Selection
          3. 8.2.1.2.3  Output Capacitor
          4. 8.2.1.2.4  Input Capacitor
          5. 8.2.1.2.5  Adjustable Undervoltage Lockout
          6. 8.2.1.2.6  Output Voltage Resistors Selection
          7. 8.2.1.2.7  Bootstrap Capacitor Selection
          8. 8.2.1.2.8  BP5 Capacitor Selection
          9. 8.2.1.2.9  PG Pullup Resistor
          10. 8.2.1.2.10 Current Limit Selection
          11. 8.2.1.2.11 Soft-Start Time Selection
          12. 8.2.1.2.12 Ramp Selection and Control Loop Stability
          13. 8.2.1.2.13 MSEL Pin
        3. 8.2.1.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
      3. 8.4.3 Thermal Performance
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.5 Switching Frequency Synchronization to an External Clock

The TPSM843A22E can be synchronized to an external clock by applying a square wave clock signal to the SYNC/FSEL pin with a duty cycle from 20% to 80%. The external clock can either be applied before the device starts up or during operation. If the external clock is applied before the device starts, a resistor from SYNC/FSEL to AGND is not needed. If the external clock is applied after the device starts, then the clock frequency must be within ±20% of the frequency set by the SYNC/FSEL resistor. When the external clock is applied after the device starts, the device begins synchronizing to this external clock after counting four consecutive switching cycles with the external clock pulse present. See Section 7.3.5.2.

Although there is no internal circuit to detect the higher 20% range of the clock frequency, it falls outside the stability range of the LC design so it is imposed as a requirement on the customer to ensure the synchronization clock is within ±20% of the frequency set by the SYNC/FSEL resistor.