SLVSHP9 July   2026 TPS544A28

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Related Products
  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  D-CAP4 Control
      2. 7.3.2  Internal VCC LDO and Using External Bias On the VCC Pin
        1. 7.3.2.1 Powering the Device From a Single Bus
        2. 7.3.2.2 Powering the Device From a Split-Rail Configuration
      3. 7.3.3  Multifunction Select (MS1) Pin
      4. 7.3.4  Multifunction Select (MS2) Pin
      5. 7.3.5  PMBus® Address (ADR) Pin
      6. 7.3.6  Output Voltage Setting
        1. 7.3.6.1 Setting VBOOT and VOUT_SCALE_LOOP
        2. 7.3.6.2 Setting Output Voltage (Internal Feedback)
        3. 7.3.6.3 Setting Output Voltage (External Feedback)
      7. 7.3.7  Switching Frequency
      8. 7.3.8  Dynamic Voltage Slew Rate
      9. 7.3.9  Enable
      10. 7.3.10 Soft Start and Soft Stop
      11. 7.3.11 Power Good
      12. 7.3.12 Overvoltage and Undervoltage Protection
      13. 7.3.13 Remote Sense
      14. 7.3.14 Low-side MOSFET Zero-Crossing
      15. 7.3.15 Current Sense and Positive Overcurrent Protection
      16. 7.3.16 Low-side MOSFET Negative Current Limit
      17. 7.3.17 Output Voltage Discharge
      18. 7.3.18 UVLO Protection
      19. 7.3.19 Telemetry
      20. 7.3.20 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Auto-Skip (PFM) Eco-mode Light Load Operation
      2. 7.4.2 Forced Continuous-Conduction Mode
  9. 8 Programming Registers
    1. 8.1 Register Map
      1. 8.1.1  OPERATION (Address = 01h)
      2. 8.1.2  ON_OFF_CONFIG (Address = 02h)
      3. 8.1.3  CLEAR_FAULTS (Address = 03h)
      4. 8.1.4  WRITE_PROTECT (Address = 10h)
      5. 8.1.5  STORE_USER_ALL (Address = 15h)
      6. 8.1.6  RESTORE_USER_ALL (Address = 16h)
      7. 8.1.7  CAPABILITY (Address = 19h)
      8. 8.1.8  VOUT_MODE (Address = 20h)
      9. 8.1.9  VOUT_COMMAND (Address = 21h)
      10.      57
      11. 8.1.10 VOUT_MARGIN_HIGH (Address = 25h)
      12. 8.1.11 VOUT_MARGIN_LOW (Address = 26h)
      13. 8.1.12 VOUT_TRANSITION_RATE (Address = 27h)
      14. 8.1.13 61
      15. 8.1.14 VOUT_SCALE_LOOP (Address = 29h)
      16. 8.1.15 FREQUENCY_SWITCH (Address = 33h)
      17. 8.1.16 64
      18. 8.1.17 VOUT_OV_FAULT_RESPONSE (Address = 41h)
      19. 8.1.18 VOUT_UV_FAULT_RESPONSE (Address = 45h)
      20. 8.1.19 IOUT_OC_FAULT_LIMIT (Address = 46h)
      21.      68
      22. 8.1.20 TON_DELAY (Address = 60h)
      23. 8.1.21 TON_RISE (Address = 61h)
      24.      71
      25. 8.1.22 TOFF_DELAY (Address = 64h)
      26. 8.1.23 TOFF_FALL (Address = 65h)
      27. 8.1.24 STATUS_BYTE (Address = 78h)
      28. 8.1.25 STATUS_WORD (Address = 79h)
      29. 8.1.26 STATUS_CML (Address = 7Eh)
      30. 8.1.27 STATUS_MFR_SPECIFIC (Address = 80h)
      31. 8.1.28 READ_VOUT (Address = 8Bh)
      32. 8.1.29 READ_IOUT (Address = 8Ch)
      33. 8.1.30 READ_TEMP1 (Address = 8Dh)
      34. 8.1.31 PMBUS_REVISION (Address = 98h)
      35. 8.1.32 MFR_ID (Address = 99h)
      36. 8.1.33 MFR_MODEL (Address = 9Ah)
      37. 8.1.34 MFR_REVISION (Address = 9Bh)
      38. 8.1.35 IC_DEVICE_ID (Address = ADh)
      39. 8.1.36 IC_DEVICE_REV (Address = AEh)
      40. 8.1.37 SYS_CFG_USER1 (Address = D1h)
      41. 8.1.38 PASSKEY (Address = D2h)
      42. 8.1.39 COMP (Address = D4h)
      43.      90
      44. 8.1.40 VBOOT (Address = D5h)
      45.      92
      46. 8.1.41 NVM_CHECKSUM (Address = D9h)
      47. 8.1.42 FUSION_ID0 (Address = FCh)
      48. 8.1.43 FUSION_ID1 (Address = FDh)
  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 Output Voltage Setting Point
        2. 9.2.2.2 Choose the Switching Frequency
        3. 9.2.2.3 Choose the Inductor
        4. 9.2.2.4 Choose the Output Capacitor
        5. 9.2.2.5 Choose the Input Capacitors (CIN)
        6. 9.2.2.6 VCC Bypass Capacitor
        7. 9.2.2.7 BOOT Capacitor
        8. 9.2.2.8 PG Pullup Resistor
        9. 9.2.2.9 Choose the PMBus® Address and Fault Recovery Mode
      3. 9.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
      3. 9.4.3 Thermal Performance On TI EVM
  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

9.2.2.2 Choose the Switching Frequency

For this design, use the internal feedback mode, and the switching frequency is configured by tying the MS1 pin to a pin-strap resistor, GND, or VCC. See also Table 7-5.

Switching frequency selection is a tradeoff between higher efficiency and smaller system design size. Lower switching frequency yields higher overall efficiency but relatively bigger external components. Higher switching frequencies cause additional switching losses which impact efficiency and thermal performance. For this design, connect MS1 pin to VCC to set the switching frequency to 800kHz

When selecting the switching frequency of a buck converter, the minimum on-time and minimum off-time must be considered. Equation 7 calculates the maximum fSW before being limited by the minimum on-time. When hitting the minimum on-time limits of a converter with D-CAP4 control, the effective switching frequency changes to keep the output voltage regulated. This calculation ignores resistive drops in the converter to give a worst case estimation.

Equation 7. f S W m a x = V O U T V I N m a x × 1 t O N _ M I N = 3.3   V 16   V × 1 25   n s = 8250   k H z

Equation 8 calculates the maximum fSW before being limited by the minimum off-time. When hitting the minimum off-time limits of a converter with D-CAP4 control, the operating duty cycle maxes out and the output voltage begins to drop with the input voltage. This equation requires the DC resistance of the inductor, RDCR, selected in the following step so this preliminary calculation assumes a resistance of 1.4mΩ. If operating near the maximum fSW limited by the minimum off-time, the variation in resistance across temperature must be considered when using Equation 9. The selected fSW of 800kHz is below the two calculated maximum values.

Equation 8. f S W m a x = V I N m i n - V O U T - I O U T m a x × R D C R + R D S O N _ H S t O F F _ M I N m a x × V I N m i n - I O U T m a x × R D S O N _ H S - R D S O N _ L S
Equation 9. f S W m a x = 8   V - 3.3   V - 12   A × 1.4   m Ω + 8.9   m Ω 150   n s × 8   V - 12   A × 8.9   m Ω - 3.3   m Ω = 3846   k H z