JAJSAJ6C May   2006  – December 2016 LM3489 , LM3489-Q1

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
  4. 4 改訂履歴
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings: LM3489
    3. 6.3 ESD Ratings: LM3489-Q1
    4. 6.4 Recommended Operating Conditions
    5. 6.5 Thermal Information
    6. 6.6 Electrical Characteristics
    7. 6.7 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
        1. 7.3.1.1 Delay
      2. 7.3.2 Current Limit Operation
      3. 7.3.3 Start Up
      4. 7.3.4 External Sense Resistor
      5. 7.3.5 PGATE
      6. 7.3.6 Adjustable UVLO
    4. 7.4 Device Functional Mode
      1. 7.4.1 Device Enable and 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 Inductor Selection (L)
        2. 8.2.2.2 Output Capacitor Selection (COUT)
        3. 8.2.2.3 Input Capacitor Selection (CIN)
        4. 8.2.2.4 Programming the Current Limit (RADJ)
        5. 8.2.2.5 Catch Diode Selection (D1)
        6. 8.2.2.6 P-Channel MOSFET Selection (Q1)
        7. 8.2.2.7 Interfacing With the Enable Pin
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
  11. 11デバイスおよびドキュメントのサポート
    1. 11.1 関連リンク
    2. 11.2 ドキュメントの更新通知を受け取る方法
    3. 11.3 コミュニティ・リソース
    4. 11.4 商標
    5. 11.5 静電気放電に関する注意事項
    6. 11.6 用語集
  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

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 Power Supply Recommendations

This device is designed to operate over a recommended input voltage supply range of 4.5 V to 35 V. The input supply must be well regulated. If the input supply is located far from the LM3485 EVM and needs a long power supply cable to connect, an additional bulk capacitor may be required. An electrolytic capacitor with a value of
47 µF can be used typically.

As mentioned in Current Limit Operation, at higher input voltages (> 28 V) an increased negative SW transient spike at the switch node can lead to an increase in the current limit threshold due to the formation of the parasitic NPN connection between the ISENSE pin, the internal substrate and the ADJ pin . To avoid this issue, a Schottky catch diode with lower forward voltage drop must be used. In addition to that, a resistor must be placed between the ISENSE pin and the external switch node. A resistor value in the range of 220 Ω to 600 Ω is recommended.