JAJSBG5H September   2003  – November 2018 LM5007

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
  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
      2. 7.3.2 High-Voltage Bias Supply Regulator
      3. 7.3.3 Overvoltage Comparator
      4. 7.3.4 On-Time Generator and Shutdown
      5. 7.3.5 Overcurrent Protection
      6. 7.3.6 N-Channel Buck Switch and Driver
      7. 7.3.7 Thermal Protection
      8. 7.3.8 Minimum Load Current
      9. 7.3.9 Ripple Configuration
    4. 7.4 Device Functional Modes
      1. 7.4.1 Standby Mode with VIN
      2. 7.4.2 Shutdown Mode
  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 Custom Design With WEBENCH® Tools
        2. 8.2.2.2 Custom Design With Excel Quickstart Tool
        3. 8.2.2.3 Feedback Resistors, RFB1 and RFB2
        4. 8.2.2.4 Switching Frequency Selection, RON
        5. 8.2.2.5 Buck Inductor, L1
        6. 8.2.2.6 Output Capacitor, COUT
        7. 8.2.2.7 Type I Ripple Circuit, RC
        8. 8.2.2.8 Input Capacitor, CIN
        9. 8.2.2.9 Current Limit, RCL
      3. 8.2.3 Application Curves
  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 デバイス・サポート
      1. 11.1.1 デベロッパー・ネットワークの製品に関する免責事項
      2. 11.1.2 WEBENCH®ツールによるカスタム設計
      3. 11.1.3 開発サポート
    2. 11.2 ドキュメントのサポート
      1. 11.2.1 関連資料
        1. 11.2.1.1 PCBレイアウトについてのリソース
        2. 11.2.1.2 熱設計についてのリソース
    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 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

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

8.2.2.9 Current Limit, RCL

Resistor RCL sets the current limit off-timer according to Equation 5. The useable values tend to be in the range of 100 kΩ to 1 MΩ. Equation 15 specifies the off-time required for volt-second balance on the inductor in current limit.

Equation 15. LM5007 q_toff-ILIM_nvs252.gif

where

  • 225 ns is the current limit response time,
  • VF is the forward voltage drop of the freewheeling power diode,
  • VOUT is the output voltage,
  • ILIM is the current limit,
  • RDCR is the inductor DC resistance.

The programmed current limit off-time should be higher than the off-time needed for volt-second balance on the inductor. For a short at the output (VOUT = 0 V) and VF = 0.7 V, an inductor DCR of 390 mΩ or higher is needed to achieve volt-second balance at the maximum programmed current limit off-time of 17 µs. Using Equation 5, an RCL of greater than 10 kΩ can be used. Select a conservative value of 100 kΩ for this design.

LM5007 TIDesignsLogo.png
For step-by-step design procedures, circuit schematics, bill of materials, PCB files, simulation and test results of LM5007-powered implementations, refer to the TI Designs reference design library.