JAJSE81B December   2017  – October 2019 LM76002-Q1 , LM76003-Q1

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     概略回路図
    2.     効率と出力電流との関係 (VOUT＝5V、fSW＝400kHz、自動モード)
  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 Timing Characteristics
    7. 6.7 Switching Characteristics
    8. 6.8 System Characteristics
    9. 6.9 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  Fixed-Frequency, Peak-Current-Mode Control
      2. 7.3.2  Light Load Operation Modes — PFM and FPWM
      3. 7.3.3  Adjustable Output Voltage
      4. 7.3.4  Enable (EN Pin) and UVLO
      5. 7.3.5  Internal LDO, VCC UVLO, and Bias Input
      6. 7.3.6  Soft Start and Voltage Tracking (SS/TRK)
      7. 7.3.7  Adjustable Switching Frequency (RT) and Frequency Synchronization
      8. 7.3.8  Minimum On-Time, Minimum Off-Time, and Frequency Foldback at Dropout Conditions
      9. 7.3.9  Internal Compensation and CFF
      10. 7.3.10 Bootstrap Voltage and VBOOT UVLO (BOOT Pin)
      11. 7.3.11 Power Good and Overvoltage Protection (PGOOD)
      12. 7.3.12 Overcurrent and Short-Circuit Protection
      13. 7.3.13 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Standby Mode
      3. 7.4.3 Active Mode
      4. 7.4.4 CCM Mode
      5. 7.4.5 DCM Mode
      6. 7.4.6 Light Load Mode
      7. 7.4.7 Foldback Mode
      8. 7.4.8 Forced Pulse-Width-Modulation Mode
      9. 7.4.9 Self-Bias Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      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  Output Voltage Setpoint
        3. 8.2.2.3  Switching Frequency
        4. 8.2.2.4  Input Capacitors
        5. 8.2.2.5  Inductor Selection
        6. 8.2.2.6  Output Capacitor Selection
        7. 8.2.2.7  Feed-Forward Capacitor
        8. 8.2.2.8  Bootstrap Capacitors
        9. 8.2.2.9  VCC Capacitors
        10. 8.2.2.10 BIAS Capacitors
        11. 8.2.2.11 Soft-Start Capacitors
        12. 8.2.2.12 Undervoltage Lockout Setpoint
        13. 8.2.2.13 PGOOD
        14. 8.2.2.14 Synchronization
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Layout Highlights
      2. 10.1.2 Compact Layout for EMI Reduction
      3. 10.1.3 Ground Plane and Thermal Considerations
      4. 10.1.4 Feedback Resistors
    2. 10.2 Layout Example
    3. 10.3 Thermal Design
  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 開発サポート
        1. 11.1.1.1 WEBENCH®ツールによるカスタム設計
    2. 11.2 ドキュメントの更新通知を受け取る方法
    3. 11.3 サポート・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

8.2 Typical Applications

The LM76002-Q1/LM76003-Q1 only requires a few external components to convert from a wide range of supply voltage to output voltage, as shown in Figure 21:

LM76002-Q1 LM76003-Q1 snvsak0a-basic-schematic.gifFigure 21. LM76002-Q1/LM76003-Q1 Basic Schematic

The LM76002-Q1/LM76003-Q1 also integrates a full list of features to aid system design requirements, such as VCC UVLO, programmable soft start, start-up tracking, programmable switching frequency, clock synchronization, and a power-good indication. Each system can select the features needed in a specific application. A comprehensive schematic with all features utilized is shown in Figure 22:

LM76002-Q1 LM76003-Q1 snvsak0a-comprehensive-schematic.gifFigure 22. LM76002-Q1/LM76003-Q1 Comprehensive Schematic

The external components must fulfill the requirements of the application, but also the stability criteria of the device control loop. The LM76002-Q1/LM76003-Q1 is optimized to work within a range of external components. Inductance and capacitance of the LC output filter each create poles that have to be considered in the control of the converter. Table 2 can be used to simplify the output filter component selection.

Table 2. Typical Component Selection

fSW (kHz) VOUT (V) L (µH) COUT (µF) RFBT (kΩ) RFBB (kΩ)
300 1 2.5 680 100 OPEN
500 1 1.5 470 100 OPEN
1000 1 0.68 200 100 OPEN
2200 1 0.47 120 100 OPEN
300 3.3 6.8 200 100 43.5
500 3.3 4.7 150 100 43.5
1000 3.3 2.5 88 100 43.5
2200 3.3 1.2 44 100 43.5
300 5 10 150 100 25
500 5 6.8 100 100 25
1000 5 3.3 66 100 25
2200 5 1.5 44 100 25
300 12 22 66 100 9.09
500 12 15 44 100 9.09
1000 12 6.8 22 100 9.09
2200 12 3.3 22 100 9.09
300 24 47 40 100 4.37
500 24 27 33 100 4.37
1000 24 15 22 100 4.37
2200 24 6.8 22 100 4.37