JAJSI67 November   2019 TPS7A52

ADVANCE INFORMATION for pre-production products; subject to change without notice.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      RFコンポーネントの電源
      2.      デジタル負荷の電源
  4. 4 改訂履歴
  5. 5 概要（続き）
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  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
    5. 7.5 Electrical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Voltage Regulation Features
        1. 8.3.1.1 DC Regulation
        2. 8.3.1.2 AC and Transient Response
      2. 8.3.2 System Start-Up Features
        1. 8.3.2.1 Programmable Soft Start (NR/SS Pin)
        2. 8.3.2.2 Internal Sequencing
          1. 8.3.2.2.1 Enable (EN)
          2. 8.3.2.2.2 Undervoltage Lockout (UVLO) Control
          3. 8.3.2.2.3 Active Discharge
        3. 8.3.2.3 Power-Good Output (PG)
      3. 8.3.3 Internal Protection Features
        1. 8.3.3.1 Foldback Current Limit (ICL)
        2. 8.3.3.2 Thermal Protection (Tsd)
    4. 8.4 Device Functional Modes
      1. 8.4.1 Regulation
      2. 8.4.2 Disabled
      3. 8.4.3 Current Limit Operation
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1  Recommended Capacitor Types
        1. 9.1.1.1 Input and Output Capacitor Requirements (CIN and COUT)
        2. 9.1.1.2 Noise-Reduction and Soft-Start Capacitor (CNR/SS)
        3. 9.1.1.3 Feed-Forward Capacitor (CFF)
      2. 9.1.2  Soft Start and Inrush Current
      3. 9.1.3  Optimizing Noise and PSRR
      4. 9.1.4  Charge Pump Noise
      5. 9.1.5  Current Sharing
      6. 9.1.6  Adjustable Operation
      7. 9.1.7  Power-Good Operation
      8. 9.1.8  Undervoltage Lockout (UVLO) Operation
      9. 9.1.9  Dropout Voltage (VDO)
      10. 9.1.10 Device Behavior During Transition From Dropout Into Regulation
      11. 9.1.11 Load Transient Response
      12. 9.1.12 Reverse Current Protection Considerations
      13. 9.1.13 Power Dissipation (PD)
      14. 9.1.14 Estimating Junction Temperature
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Board Layout
    2. 11.2 Layout Example
  12. 12デバイスおよびドキュメントのサポート
    1. 12.1 デバイス・サポート
      1. 12.1.1 開発サポート
        1. 12.1.1.1 リファレンス・デザイン
      2. 12.1.2 デバイスの項目表記
    2. 12.2 ドキュメントのサポート
      1. 12.2.1 関連資料
    3. 12.3 ドキュメントの更新通知を受け取る方法
    4. 12.4 コミュニティ・リソース
    5. 12.5 商標
    6. 12.6 静電気放電に関する注意事項
    7. 12.7 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

8.3.1.1 DC Regulation

A low dropout regulator (LDO) functions as a class-B amplifier, as shown in Figure 1, in which the input signal is the internal reference voltage (VREF). VREF is designed to have very low bandwidth at the input to the error amplifier through the use of a low-pass filter (VNR/SS).

As such, the reference can be considered as a pure dc input signal. The low output impedance of an LDO comes from the combination of the output capacitor and pass element. The pass element also presents a high input impedance to the source voltage when operating as a current source. A positive LDO can only source current because of the class-B architecture.

This device achieves a maximum of 1% output voltage accuracy primarily because of the high-precision band-gap voltage (VBG) that creates VREF. The low dropout voltage (VDO) reduces the thermal power dissipation required by the device to regulate the output voltage at a given current level, thereby improving system efficiency. These features combine to make this device a good approximation of an ideal voltage source.

TPS7A52 fb_ldo_classb_sbvs291.gif

NOTE:

VOUT = VREF × (1 + R1 / R2).
Figure 1. Simplified Regulation Circuit