JAJSL91 april   2021 LM117QML-SP

PRODUCTION DATA  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  5. 4 Revision History
  6. 5 Device Comparison Table
  7. 6 Pin Configurations and Functions
  8. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information
    5. 7.5  Electrical Characteristics: 0.5–A IOUT Devices (LM117H, LM117GW)
    6. 7.6  Parameter Drift: 0.5–A IOUT Devices (LM117H, LM117GW)
    7. 7.7  Electrical Characteristics: 1.5–A IOUT Devices (LM117K)
    8. 7.8  Parameter Drift: 1.5–A IOUT Devices (LM117K)
    9. 7.9  Quality Conformance Inspection
    10. 7.10 Typical Characteristics
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Setting Output Voltage
    4. 8.4 External Capacitors
    5. 8.5 Load Regulation
    6. 8.6 Protection Diodes
  10. 9 Application and Implementation
    1. 9.1 Typical Applications
  11. 10Power Supply Recommendations
  12. 11Layout
    1. 11.1 Layout Guidelines
  13. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 サード・パーティ製品に関する免責事項
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 ドキュメントの更新通知を受け取る方法
    4. 12.4 サポート・リソース
    5. 12.5 Trademarks
    6. 12.6 静電気放電に関する注意事項
    7. 12.7 用語集

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

8.3 Setting Output Voltage

In operation, the LM117 develops a nominal 1.25-V reference voltage, VREF, between the output and adjustment terminal. The reference voltage is expressed across R1 and, since the voltage is constant, a constant current I1 then flows through R2, giving an output voltage found by using Equation 1.

Equation 1. GUID-F14BA8D8-F8F5-44E5-96DF-67ECE66C2D75-low.png
GUID-F86FACDA-E546-4507-8F78-CBE2D08C0CE8-low.png

Since the 100-μA current from the adjustment terminal represents an error term, the LM117 was designed to minimize IADJ and make it relatively constant with line and load changes. To do this, all quiescent operating current is returned to the output establishing a minimum load current requirement. If there is insufficient load on the output, the output will rise.

To mitigate the requirement for an added load to sink the required output current, the resistor divider may be selected so that it alone can sink the largest specified output load current of 5 mA. This has the additional benefit of minimizing the IADJ error term (which varies over temperature).