JAJSFN3C June   2018  – October 2020 LMR33630-Q1

PRODUCTION DATA  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
  4. 4 Revision History
  5. 5 Pin Configuration and 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 System Characteristics
    8. 6.8 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 Power-Good Flag Output
      2. 7.3.2 Enable and Start-up
      3. 7.3.3 Current Limit and Short Circuit
      4. 7.3.4 Undervoltage Lockout and Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Auto Mode
      2. 7.4.2 Dropout
      3. 7.4.3 Minimum Switch On-Time
  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  Choosing the Switching Frequency
        3. 8.2.2.3  Setting the Output Voltage
        4. 8.2.2.4  Inductor Selection
        5. 8.2.2.5  Output Capacitor Selection
        6. 8.2.2.6  Input Capacitor Selection
        7. 8.2.2.7  CBOOT
        8. 8.2.2.8  VCC
        9. 8.2.2.9  CFF Selection
        10. 8.2.2.10 External UVLO
        11. 8.2.2.11 Maximum Ambient Temperature
      3. 8.2.3 Application Curves
    3. 8.3 What to Do and What Not to Do
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Ground and Thermal Considerations
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
        1. 11.1.1.1 Custom Design With WEBENCH® Tools
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 サポート・リソース
    4. 11.4 ドキュメントの更新通知を受け取る方法
    5. 11.5 Trademarks
    6. 11.6 静電気放電に関する注意事項
    7. 11.7 用語集

パッケージ・オプション

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メカニカル・データ（パッケージ｜ピン）
  • RNX|12
サーマルパッド・メカニカル・データ
発注情報

7.3.2 Enable and Start-up

Start-up and shutdown are controlled by the EN input. This input features precision thresholds, allowing the use of an external voltage divider to provide an adjustable input UVLO (see Section 8.2.2.10). Applying a voltage of ≥ VEN-VCC_H causes the device to enter standby mode, powering the internal VCC, but not producing an output voltage. Increasing the EN voltage to VEN-H fully enables the device, allowing it to enter start-up mode and start the soft-start period. When the EN input is brought below VEN-H by VEN-HYS, the regulator stops running and enters standby mode. Further decrease in the EN voltage to below VEN-VCC-L completely shuts down the device. This behavior is shown in Figure 7-3. The EN input can be connected directly to VIN if this feature is not needed. This input must not be allowed to float. The values for the various EN thresholds can be found in Section 6.5.

The LMR33630-Q1 uses a reference-based soft start that prevents output voltage overshoots and large inrush currents as the regulator is starting up. A typical start-up waveform is shown in Figure 7-4, indicating typical timings. The rise time of the output voltage is about 4 ms (see the Section 6.5).

GUID-0DD24FB0-B134-489B-BC07-A929D652B74A-low.gifFigure 7-3 Precision Enable Behavior
GUID-C0A50726-ADCD-47FD-812F-C2F6581D5A46-low.gifFigure 7-4 Typical Start-up Behavior VIN = 12 V, VOUT = 5 V, IOUT = 3 A