JAJSBA0Q January   2000  – December 2017 LP2950-N , LP2951-N

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
    1.     LP2951の概略回路図
  3. 3 概要
    1.     LP2950-Nの概略回路図
  4. 4 改訂履歴
  5. 5 Voltage Options
  6. 6 Pin Configuration and Functions
    1.     Pin Functions: LP2950-N
    2.     Pin Functions: LP2951-N
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information: LP2950-N
    5. 7.5 Thermal Information: LP2951-N
    6. 7.6 Electrical Characteristics
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagrams
    3. 8.3 Feature Description
      1. 8.3.1 Fixed Voltage Options and Programmable Voltage Version
      2. 8.3.2 High Accuracy Output Voltage
      3. 8.3.3 Low Dropout Voltage
      4. 8.3.4 Shutdown Mode
      5. 8.3.5 Error Detection Comparator Output
      6. 8.3.6 Internal Protection Circuitry
        1. 8.3.6.1 Short-Circuit Protection (Current Limit)
        2. 8.3.6.2 Thermal Protection
      7. 8.3.7 Enhanced Stability
    4. 8.4 Device Functional Modes
      1. 8.4.1 Operation with 30 V ≥ VIN > VOUT(TARGET) + 1 V
      2. 8.4.2 Operation with Shutdown Control
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1  1-A Regulator with 1.2-V Dropout
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Output Capacitor Requirements
          2. 9.2.1.2.2 Input Capacitor Requirements
          3. 9.2.1.2.3 Error Detection Comparator Output
          4. 9.2.1.2.4 Programming the Output Voltage (LP2951-N)
          5. 9.2.1.2.5 Reducing Output Noise
        3. 9.2.1.3 Application Curves
      2. 9.2.2  300-mA Regulator with 0.75-V Dropout
      3. 9.2.3  Wide Input Voltage Range Current Limiter
      4. 9.2.4  Low Drift Current Source
      5. 9.2.5  5-V Current Limiter
      6. 9.2.6  Regulator with Early Warning and Auxiliary Output
      7. 9.2.7  Latch Off When Error Flag Occurs
      8. 9.2.8  2-A Low Dropout Regulator
      9. 9.2.9  5-V Regulator with 2.5-V Sleep Function
      10. 9.2.10 Open Circuit Detector for 4 → 20-mA Current Loop
      11. 9.2.11 Regulator with State-of-Charge Indicator
      12. 9.2.12 Low Battery Disconnect
      13. 9.2.13 System Overtemperature Protection Circuit
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 WSON Mounting
  12. 12デバイスおよびドキュメントのサポート
    1. 12.1 ドキュメントのサポート
      1. 12.1.1 関連資料
    2. 12.2 関連リンク
    3. 12.3 コミュニティ・リソース
    4. 12.4 商標
    5. 12.5 静電気放電に関する注意事項
    6. 12.6 Glossary
  13. 13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

9.2.6 Regulator with Early Warning and Auxiliary Output

The LP2951 can be used to build a Regulator with early warning and auxiliary output as Figure 48 shows. it has below features:

  • Early warning flag on low input voltage
  • Main output latches off at lower input voltages
  • Battery backup on auxiliary output
  • Operation: VOUT of regulator 1 is programmed one diode drop above 5 V. Its error flag becomes active when VIN ≤ 5.7 V. When VIN drops below 5.3 V, the error flag of regulator 2 becomes active and via Q1 latches the main output off. When VIN again exceeds 5.7 V regulator 1 is back in regulation and the early warning signal rises, unlatching regulator 2 via D3.

LP2950-N LP2951-N 854611.png
Figure 48. Regulator With Early Warning and Auxiliary Output