JAJSAU0I September   2007  – January 2018 LM3102

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の回路図
      2.      効率と負荷電流との関係(VOUT＝3.3V)
  4. 4 改訂履歴
  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 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  COT Control Circuit Overview
      2. 7.3.2  Start-Up Regulator (VCC)
      3. 7.3.3  Regulation Comparator
      4. 7.3.4  Zero Coil Current Detect
      5. 7.3.5  Overvoltage Comparator
      6. 7.3.6  Current Limit
      7. 7.3.7  N-Channel MOSFET and Driver
      8. 7.3.8  Soft-Start
      9. 7.3.9  Thermal Protection
      10. 7.3.10 Thermal Derating
    4. 7.4 Device Functional Modes
      1. 7.4.1 ON-Time Timer, Shutdown
  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 Design Steps for the LM3102 Application
        2. 8.2.2.2 External Components
      3. 8.2.3 Application Curve
    3. 8.3 System Examples
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11デバイスおよびドキュメントのサポート
    1. 11.1 コミュニティ・リソース
    2. 11.2 商標
    3. 11.3 静電気放電に関する注意事項
    4. 11.4 Glossary
  12. 12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

デバイスごとのパッケージ図は、PDF版データシートをご参照ください。

メカニカル・データ（パッケージ｜ピン）
  • YPA|28
  • PWP|20
サーマルパッド・メカニカル・データ
発注情報

7.3.8 Soft-Start

The soft-start feature allows the converter to gradually reach a steady-state operating point, thereby reducing startup stresses and current surges. Upon turnon, after VCC reaches the undervoltage threshold, an 8-µA internal current source charges up an external capacitor CSS connecting to the SS pin. The ramping voltage at the SS pin (and the non-inverting input of the regulation comparator as well) ramps up the output voltage VOUT in a controlled manner.

An internal switch grounds the SS pin if any of the following three cases happens: (i) VCC is below the UVLO threshold; (ii) a thermal shutdown occurs; or (iii) the EN pin is grounded. Alternatively, the output voltage can be shut off by connecting the SS pin to ground using an external switch. Releasing the switch allows the SS pin to ramp up and the output voltage to return to normal. The shutdown configuration is shown in Figure 21.

LM3102 30021327.pngFigure 21. Alternate Shutdown Implementation