SLUSB56B November   2012  – April 2019 TPS53819A

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Application
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 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 Timing Requirements
    7. 6.7 Switching Characteristics
    8. 6.8 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Enable and Soft-Start
      2. 7.3.2  Adaptive On-Time Control
      3. 7.3.3  Zero Crossing Detection
      4. 7.3.4  Output Discharge Control
      5. 7.3.5  Low-Side Driver
      6. 7.3.6  High-Side Driver
      7. 7.3.7  Power Good
      8. 7.3.8  Current Sense and Overcurrent Protection
      9. 7.3.9  Overvoltage and Undervoltage Protection
      10. 7.3.10 Out-of-Bound Protection
      11. 7.3.11 UVLO Protection
      12. 7.3.12 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Light-Load Condition in Auto-Skip Operation (Eco-mode)
      2. 7.4.2 Forced Continuous Conduction Mode
      3. 7.4.3 D-CAP2™ Mode
    5. 7.5 Programming
      1. 7.5.1 PMBus General Descriptions
      2. 7.5.2 PMBus Slave Address Selection
      3. 7.5.3 PMBus Address Selection
      4. 7.5.4 Supported Formats
        1. 7.5.4.1 Direct Format: Write
        2. 7.5.4.2 Combined Format: Read
        3. 7.5.4.3 Stop-Separated Reads
      5. 7.5.5 Supported PMBus Commands
      6. 7.5.6 Unsupported PMBus Commands
    6. 7.6 Register Maps
      1. 7.6.1  OPERATION [01h] (R/W Byte)
      2. 7.6.2  ON_OFF_CONFIG [02h] (R/W Byte)
      3. 7.6.3  WRITE_PROTECT [10h] (R/W Byte)
      4. 7.6.4  CLEAR_FAULTS [03h] (Send Byte)
      5. 7.6.5  STORE_DEFAULT_ALL [11h] (Send Byte)
      6. 7.6.6  RESTORE_DEFAULT_ALL [12h] (Send Byte)
      7. 7.6.7  STATUS_WORD [79h] (Read Word)
      8. 7.6.8  CUSTOM_REG (MFR_SPECIFIC_00) [D0h] (R/W Byte)
      9. 7.6.9  DELAY_CONTROL (MFR_SPECIFIC_01) [D1h] (R/W Byte)
      10. 7.6.10 MODE_SOFT_START_CONFIG (MFR_SPECIFIC_02) [D2h] (R/W Byte)
      11. 7.6.11 FREQUENCY_CONFIG (MFR_SPECIFIC_03) [D3h] (R/W Byte)
      12. 7.6.12 VOUT_ADJUSTMENT (MFR_SPECIFIC_04) [D4h] (R/W Byte)
      13. 7.6.13 Output Voltage Fine Adjustment Soft Slew Rate
      14. 7.6.14 VOUT_MARGIN (MFR_SPECIFIC_05) [D5h] (R/W Byte)
      15. 7.6.15 Output Voltage Margin Adjustment Soft-Slew Rate
      16. 7.6.16 UVLO_THRESHOLD (MFR_SPECIFIC_06) [D6h]
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      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  Switching Frequency
        3. 8.2.2.3  Inductor (L1)
        4. 8.2.2.4  Output Capacitors (C10, C11, C12, C13, C14)
        5. 8.2.2.5  Input Capacitors (C1, C2, C3, C4, C5)
        6. 8.2.2.6  MOSFET (Q1, Q2)
        7. 8.2.2.7  VREG Bypass Capacitor (C18)
        8. 8.2.2.8  VDD Bypass Capacitor (C19)
        9. 8.2.2.9  VBST Capacitor (C7)
        10. 8.2.2.10 Snubber (C8 and R9)
        11. 8.2.2.11 Feedback Resistance, RFBH and RFBL (R17 and R18)
        12. 8.2.2.12 Overcurrent Limit (OCL) Setting Resistance (R10)
        13. 8.2.2.13 PMBus Device Address (R3 and R4)
        14. 8.2.2.14 PGOOD Pullup Resistor (R2)
        15. 8.2.2.15 SCL and SDA Pulldown Resistors (R14 and R15)
        16. 8.2.2.16 PMBus Pullup Resistors
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
        1. 11.1.1.1 Custom Design With WEBENCH® Tools
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.2.3 Inductor (L1)

Determined the inducatance to yield a ripple current (IIND(ripple)) of approximately ¼ to ½ of maximum output current. Larger ripple current increases output ripple voltage, improves the signal-to-noise ratio and helps stable operation. Maximum current ripple occurs with the maximum input voltage. Equation 9 calculates the recommended inductance. After choosing the inductance, use Equation 10 to calculate the ripple.

Equation 9. TPS53819A q_l_lusau9.gif
Equation 10. TPS53819A q_iindripple_lusau9.gif

The inductor requires a low DCR to achieve good efficiency. The inductor also requires enough margin above the peak inductor current before saturation. The peak inductor current can be estimated in Equation 11.

Equation 11. TPS53819A q_iindpeak_lusau9.gif

Using Equation 9 the recommended inductance for the example is 0.329 μH. An inductor supplied by Pulse Electronics (PA0513.441NLT) is selected with an inductance of 0.440 μH at 0 A and 0.363 μH at its 30 A rated current. The saturation current is 35 A and the DCR is 0.32 mΩ. Using Equation 10 with the selected inductance and maximum input voltage, the current ripple is estimated to be 6.23 A. Equation 11 calculates the peak current to be 31.3 A, well below the saturation current of the inductor. The output current threshold when the supply operates in DCM or CCM can also be estimated as half the estimated current ripple. With the maximum 14 V input in this design the output current threshold is 3.12 A. With lower input voltages, ripple decreases and so does the threshold.