JAJSGC8B October   2018  – January 2020 TPS25982

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
  4. 4 改訂履歴
  5. 5 デバイス比較表
  6. 6 概要 (続き)
  7. 7 Pin Configuration and Functions
    1.     Pin Functions
  8. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 Timing Requirements
    7. 8.7 Switching Characteristics
    8. 8.8 Typical Characteristics
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Undervoltage Protection (UVLO and UVP)
      2. 9.3.2 Overvoltage Protection (OVP)
      3. 9.3.3 Inrush Current, Overcurrent, and Short-Circuit Protection
        1. 9.3.3.1 Slew Rate and Inrush Current Control (dVdt)
        2. 9.3.3.2 Circuit Breaker
        3. 9.3.3.3 Active Current Limiting
        4. 9.3.3.4 Short-Circuit Protection
      4. 9.3.4 Overtemperature Protection (OTP)
      5. 9.3.5 Analog Load Current Monitor (IMON)
      6. 9.3.6 Power Good (PG)
      7. 9.3.7 Load Detect/Handshake (LDSTRT)
    4. 9.4 Fault Response
    5. 9.5 Device Functional Modes
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application: Standby Power Rail Protection in Datacenter Servers
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Device Selection
        2. 10.2.2.2 Setting the Current Limit Threshold: RILIM Selection
        3. 10.2.2.3 Setting the Undervoltage Lockout Set Point
        4. 10.2.2.4 Choosing the Current Monitoring Resistor: RIMON
        5. 10.2.2.5 Setting the Output Voltage Ramp Time (TdVdt)
          1. 10.2.2.5.1 Case 1: Start-Up Without Load: Only Output Capacitance COUT Draws Current
          2. 10.2.2.5.2 Case 2: Start-Up With Load: Output Capacitance COUT and Load Draw Current
        6. 10.2.2.6 Setting the Load Handshake (LDSTRT) Delay
        7. 10.2.2.7 Setting the Transient Overcurrent Blanking Interval (tITIMER)
        8. 10.2.2.8 Setting the Auto-Retry Delay and Number of Retries
      3. 10.2.3 Application Curves
    3. 10.3 System Examples
      1. 10.3.1 Optical Module Power Rail Path Protection
        1. 10.3.1.1 Design Requirements
        2. 10.3.1.2 Device Selection
        3. 10.3.1.3 External Component Settings
        4. 10.3.1.4 Voltage Drop
        5. 10.3.1.5 Application Curves
      2. 10.3.2 Input Protection for 12-V Rail Applications: PCIe Cards, Storage Interfaces and DC Fans
  11. 11Power Supply Recommendations
    1. 11.1 Transient Protection
    2. 11.2 Output Short-Circuit Measurements
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13デバイスおよびドキュメントのサポート
    1. 13.1 ドキュメントのサポート
      1. 13.1.1 関連資料
        1. 13.1.1.1 関連リンク
    2. 13.2 ドキュメントの更新通知を受け取る方法
    3. 13.3 コミュニティ・リソース
    4. 13.4 商標
    5. 13.5 静電気放電に関する注意事項
    6. 13.6 Glossary
  14. 14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

11.1 Transient Protection

In the case of a short circuit and overload current limit when the device interrupts current flow, the input inductance generates a positive voltage spike on the input, and the output inductance generates a negative voltage spike on the output. The peak amplitude of voltage spikes (transients) is dependent on the value of inductance in series to the input or output of the device. Such transients can exceed the absolute maximum ratings of the device if steps are not taken to address the issue. Typical methods for addressing transients include:

  • Minimize lead length and inductance into and out of the device.
  • Use a large PCB GND plane.
  • Use a Schottky diode across the output to absorb negative spikes.
  • Use a low value ceramic capacitor CIN = 0.001 μF to 0.1 μF to absorb the energy and dampen the transients. The approximate value of input capacitance can be estimated using Equation 30.
Equation 30. TPS25982 Equation-VIN-spike.gif

where

  • VIN is the nominal supply voltage
  • ILOAD is the load current
  • LIN equals the effective inductance seen looking into the source
  • CIN is the capacitance present at the input

Some of the applications may require the addition of a Transient Voltage Suppressor (TVS) to prevent transients from exceeding the absolute maximum ratings of the device. A typical circuit implementation with optional protection components (a ceramic capacitor, TVS and Schottky diode) is shown in Figure 72.

TPS25982 Circuit-with-transient-protection-components.gifFigure 72. Typical Circuit Implementation With Optional Protection Components