JAJSFB3 April   2018 LM25119Q

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      代表的なアプリケーション回路
  4. 4 改訂履歴
  5. 5 概要（続き）
  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 Switching Characteristics
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  High Voltage Start-Up Regulator
      2. 8.3.2  UVLO
      3. 8.3.3  Enable 2
      4. 8.3.4  Oscillator and Sync Capability
      5. 8.3.5  Error Amplifiers and PWM Comparators
      6. 8.3.6  Ramp Generator
      7. 8.3.7  Current Limit
      8. 8.3.8  Hiccup Mode Current Limiting
      9. 8.3.9  Soft Start
      10. 8.3.10 HO and LO Output Drivers
      11. 8.3.11 Maximum Duty Cycle
      12. 8.3.12 Thermal Protection
    4. 8.4 Device Functional Modes
      1. 8.4.1 Diode Emulation
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Miscellaneous Functions
      2. 9.1.2 Interleaved Two-Phase Operation
      3. 9.1.3 Interleaved 4-Phase Operation
    2. 9.2 Typical Applications
      1. 9.2.1 Dual-output Design Example
        1. 9.2.1.1 Design Requirements
          1. 9.2.1.1.1 External Components
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1  Timing Resistor
          2. 9.2.1.2.2  Output Inductor
          3. 9.2.1.2.3  Current Sense Resistor
          4. 9.2.1.2.4  Ramp Resistor and Ramp Capacitor
          5. 9.2.1.2.5  Output Capacitors
          6. 9.2.1.2.6  Input Capacitors
          7. 9.2.1.2.7  VCC Capacitor
          8. 9.2.1.2.8  Bootstrap Capacitor
          9. 9.2.1.2.9  Soft Start Capacitor
          10. 9.2.1.2.10 Restart Capacitor
          11. 9.2.1.2.11 Output Voltage Divider
          12. 9.2.1.2.12 UVLO Divider
          13. 9.2.1.2.13 MOSFET Selection
          14. 9.2.1.2.14 MOSFET Snubber
          15. 9.2.1.2.15 Error Amplifier Compensation
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Two-Phase Design Example
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Switching Jitter Root Causes and Solutions
    2. 11.2 Layout Example
  12. 12デバイスおよびドキュメントのサポート
    1. 12.1 コミュニティ・リソース
    2. 12.2 商標
    3. 12.3 静電気放電に関する注意事項
    4. 12.4 Glossary
  13. 13メカニカル、パッケージ、および注文情報

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

9.2.1.2.11 Output Voltage Divider

RFB1 and RFB2 set the output voltage level, the ratio of these resistors is calculated from Equation 33.

Equation 33. LM25119Q 30126253.gif

Choosing a value of 2.21 kΩ for RFB1 results in a RFB2 value of 6.98 kΩ for a VOUT1 of 3.3 V. A reasonable guide is to select the value of RFB1 in the range between 500 Ω and 10 kΩ. The value of RFB1 must be large enough to keep the total divider power dissipation small.

LM25119Q fb_config_slusd97.gifFigure 16. Feedback Configuration