JAJSAH6H January   2006  – October 2017 LM3100

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
  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 Hysteretic Control Circuit Overview
    4. 7.4 Device Functional Modes
      1. 7.4.1 Start-up Regulator (VCC)
      2. 7.4.2 Regulation Comparator
      3. 7.4.3 Over-Voltage Comparator
      4. 7.4.4 ON-Time Timer, Shutdown
      5. 7.4.5 Current Limit
      6. 7.4.6 N-Channel Buck Switch and Driver
      7. 7.4.7 Soft-Start
      8. 7.4.8 Thermal Protection
  8. 8 Applications and Implementation
    1. 8.1 Applications Information
      1. 8.1.1 External Components
        1. 8.1.1.1 RFB1 and RFB2
        2. 8.1.1.2 RON
        3. 8.1.1.3 L
        4. 8.1.1.4 CVCC
        5. 8.1.1.5 CO and CO3
        6. 8.1.1.6 CIN and CIN3
        7. 8.1.1.7 CBST
        8. 8.1.1.8 CSS
        9. 8.1.1.9 CFB
    2. 8.2 Typical Application
  9. 9 Layout
    1. 9.1 Layout Guidelines
      1. 9.1.1 PC Board Layout
  10. 10デバイスおよびドキュメントのサポート
    1. 10.1 ドキュメントの更新通知を受け取る方法
    2. 10.2 コミュニティ・リソース
    3. 10.3 商標
    4. 10.4 静電気放電に関する注意事項
    5. 10.5 Glossary
  11. 11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

7.4.7 Soft-Start

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

An internal switch grounds the SS pin if any of the following cases happen: (i) VCC falls below the under-voltage lock-out threshold; (ii) a thermal shutdown occurs; or (iii) the EN pin is grounded. Alternatively, the converter can be disabled by connecting the SS pin to ground using an external switch. Releasing the switch allows the SS pin return to pull high and the output voltage returns to normal. The shut-down configuration is shown in Figure 21 .

LM3100 20174706.gifFigure 21. Alternate Shutdown Implementation