SLVSA67F February   2010  – April 2020 TPS62400-Q1 , TPS62402-Q1 , TPS62404-Q1 , TPS62405-Q1

UNLESS OTHERWISE NOTED, this document contains PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
      2.      TPS62402-Q1 Efficiency versus Output Current, VOUT1 and VOUT2
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements
    7. 7.7 Switching Characteristics
    8. 7.8 Typical Characteristics
  8. 8 Parameter Measurement Information
  9. 9 Detailed Description
    1. 9.1 Overview
      1. 9.1.1 Converter 1
      2. 9.1.2 Converter 2
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Enable
      2. 9.3.2 DEF_1 Pin Function
      3. 9.3.3 180° Out-of-Phase Operation
      4. 9.3.4 Short-Circuit Protection
      5. 9.3.5 Thermal Shutdown
      6. 9.3.6 EasyScale Interface: One-Pin Serial Interface for Dynamic Output-Voltage Adjustment
        1. 9.3.6.1 General
        2. 9.3.6.2 Protocol
    4. 9.4 Device Functional Modes
      1. 9.4.1 Power-Save Mode
        1. 9.4.1.1 Dynamic Voltage Positioning
        2. 9.4.1.2 Soft Start
        3. 9.4.1.3 100% Duty-Cycle Low-Dropout Operation
        4. 9.4.1.4 Undervoltage Lockout
      2. 9.4.2 Mode Selection
    5. 9.5 Programming
      1. 9.5.1 Addressable Registers
        1. 9.5.1.1 Bit Decoding
        2. 9.5.1.2 Acknowledge
        3. 9.5.1.3 Mode Selection
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Output Voltage Setting
          1. 10.2.2.1.1 Converter 1 Adjustable Default Output-Voltage Setting: TPS62400-Q1
          2. 10.2.2.1.2 Converter 1 Fixed Default Output-Voltage Setting (TPS62402-Q1, TPS62404-Q1, and TPS62405-Q1)
          3. 10.2.2.1.3 Converter 2 Adjustable Default Output-Voltage Setting (TPS62400-Q1):
          4. 10.2.2.1.4 Converter 2 Fixed Default Output-Voltage Setting
        2. 10.2.2.2 Output Filter Design (Inductor and Output Capacitor)
          1. 10.2.2.2.1 Inductor Selection
          2. 10.2.2.2.2 Output-Capacitor Selection
          3. 10.2.2.2.3 Input Capacitor Selection
      3. 10.2.3 Application Curves
    3. 10.3 System Examples
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Third-Party Products Disclaimer
    2. 13.2 Related Links
    3. 13.3 Support Resources
    4. 13.4 Trademarks
    5. 13.5 Electrostatic Discharge Caution
    6. 13.6 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

10.2.2.2.1 Inductor Selection

Select the inductor based on its ratings for dc resistance and saturation current. The dc resistance of the inductor directly influences the efficiency of the converter. Therefore, select an inductor with lowest dc resistance for highest efficiency.

Equation 6 calculates the maximum inductor current under static load conditions. The saturation-current rating of the inductor must be higher than the maximum inductor current as calculated with Equation 7. TI makes this recommendation because during heavy load transients, the inductor current rises above the calculated value.

Equation 6. TPS62400-Q1 TPS62402-Q1 TPS62404-Q1 TPS62405-Q1 q6_deltai_slvsa67.gif

where

  • ΔIL = peak-to-peak inductor ripple current
  • L = inductor value
  • fSW = switching frequency (2.25 MHz typical)
Equation 7. TPS62400-Q1 TPS62402-Q1 TPS62404-Q1 TPS62405-Q1 q7_ilmax_slvsa67.gif

where

  • ILmax = maximum inductor current and the highest inductor current occurs at maximum VIN

Open-core inductors have a soft saturation characteristic and they can usually handle higher inductor currents versus a comparable shielded inductor.

A more conservative approach is to select the inductor current rating just for the maximum switch current of the corresponding converter. Take into consideration that the core material from inductor to inductor differs, and this difference has an impact on the efficiency.

See Table 7 and the typical application circuit examples for possible inductors.

Table 7. List of Inductors

DIMENSIONS [mm] INDUCTOR TYPE SUPPLIER
3.2 × 2.6 × 1 MIPW3226 FDK
3 × 3 × 0.9 LPS3010 Coilcraft
2.8 × 2.6 × 1 VLF3010 TDK
2.8 x 2.6 × 1.4 VLF3014 TDK
3 × 3 × 1.4 LPS3015 Coilcraft
3.9 × 3.9 × 1.7 LPS4018 Coilcraft