JAJSLH2 March   2021 TPS62810M , TPS62811M , TPS62812M , TPS62813M

PRODUCTION DATA  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and 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 Typical Characteristics
  8. 8 Parameter Measurement Information
    1. 8.1 Schematic
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Precise Enable
      2. 9.3.2 COMP/FSET
      3. 9.3.3 MODE/SYNC
      4. 9.3.4 Spread Spectrum Clocking (SSC)
      5. 9.3.5 Undervoltage Lockout (UVLO)
      6. 9.3.6 Power Good Output (PG)
      7. 9.3.7 Thermal Shutdown
    4. 9.4 Device Functional Modes
      1. 9.4.1 Pulse Width Modulation (PWM) Operation
      2. 9.4.2 Power Save Mode Operation (PWM/PFM)
      3. 9.4.3 100% Duty-Cycle Operation
      4. 9.4.4 Current Limit and Short Circuit Protection
      5. 9.4.5 Foldback Current Limit and Short Circuit Protection
      6. 9.4.6 Output Discharge
      7. 9.4.7 Soft Start/Tracking (SS/TR)
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Programming the Output Voltage
      2. 10.1.2 Inductor Selection
      3. 10.1.3 Capacitor Selection
        1. 10.1.3.1 Input Capacitor
        2. 10.1.3.2 Output Capacitor
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
      3. 10.2.3 Application Curves
    3. 10.3 System Examples
      1. 10.3.1 Voltage Tracking
      2. 10.3.2 Synchronizing to an External Clock
  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 Documentation Support
      1. 13.2.1 Related Documentation
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 サポート・リソース
    5. 13.5 Trademarks
    6. 13.6 静電気放電に関する注意事項
    7. 13.7 用語集
  14. 14Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

10.1.2 Inductor Selection

The TPS6281xM device is designed for a nominal 0.47-µH inductor with a typical switching frequency of 2.25 MHz. Larger values can be used to achieve a lower inductor current ripple, but they can have a negative impact on efficiency and transient response. Smaller values than 0.47 µH cause a larger inductor current ripple, which causes larger negative inductor current in forced PWM mode at low or no output current. For a higher or lower nominal switching frequency, the inductance must be changed accordingly.

The inductor selection is affected by several effects like the following:

  • Inductor ripple current
  • Output ripple voltage
  • PWM-to-PFM transition point
  • Efficiency
In addition, the selectec inductor has to be rated for appropriate saturation current and DC resistance (DCR). Equation 8 calculates the maximum inductor current.

Equation 8. GUID-4F0D3DC8-2030-435E-B616-2E7A317F2EC3-low.gif
Equation 9. GUID-F4CBEDD7-6AA3-4C6F-9A39-9E2168EE9DCA-low.gif

where

  • IL(max) is the maximum inductor current
  • ΔIL(max) is the peak-to-peak inductor ripple current
  • Lmin is the minimum inductance at the operating point
Table 10-1 Typical Inductors
TYPE INDUCTANCE [µH] CURRENT [A] (1) FOR DEVICE NOMINAL SWITCHING FREQUENCY DIMENSIONS [LxBxH] mm MANUFACTURER(2)

OPERATION AT –55°C
ML433PYA601MLZ 0.6 µH, ±20% 10.4 TPS62810M, TPS62813M, TPS62812M 2.25 MHz 4 × 4 × 2.1 Coilcraft

yes
ML433PYA401MLZ 0.4 µH, ±20% 12.5 TPS62810M, TPS62813M, TPS62812M 2.25 MHz 4 × 4 × 2.1 Coilcraft

yes
XFL4015-471ME 0.47 µH, ±20% 3.5 TPS62813M, TPS62812M 2.25 MHz 4 × 4 × 1.6 Coilcraft

no
XEL4020-561ME 0.56 µH, ±20% 9.9 TPS62810M, TPS62813M, TPS62812M 2.25 MHz 4 × 4 × 2.1 Coilcraft

no
XEL4030-471ME 0.47 µH, ±20% 12.3 TPS62810M, TPS62813M, TPS62812M 2.25 MHz 4 × 4 × 3.1 Coilcraft

no
XEL3515-561ME 0.56 µH, ±20% 4.5 TPS62813M, TPS62812M 2.25 MHz 3.5 × 3.2 × 1.5 Coilcraft

no
XFL3012-331MEB 0.33 µH, ±20% 2.6 TPS62811M, TPS62812M ≥ 3.5 MHz 3 × 3 × 1.3 Coilcraft

no
XPL2010-681ML 0.68 µH, ±20% 1.5 TPS62811M 2.25 MHz 2 × 1.9 × 1 Coilcraft

no
DFE252012PD-R47M 0.47 µH, ±20% see data sheet TPS62811M, TPS62813M, TPS62812M 2.25 MHz 2.5 × 2 × 1.2 Murata

no
(1) Lower of IRMS at 20°C rise or ISAT at 20% drop

Calculating the maximum inductor current using the actual operating conditions gives the minimum saturation current of the inductor needed. A margin of about 20% is recommended to add. A larger inductor value is also useful to get lower ripple current, but increases the transient response time and size as well.