JAJSMO5C August   2000  – August 2021 DCV010505 , DCV010505D , DCV010512 , DCV010512D , DCV010515 , DCV010515D , DCV011512D , DCV011515D , DCV012405 , DCV012415D

PRODUCTION DATA  

  1. 特長
  2. アプリケーション
  3. 概要
  4. Revision History
  5. Device Comparison Table
  6. Pin Configuration and Functions
  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
    6. 7.6 Switching Characteristics
    7. 7.7 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagrams
    3. 8.3 Feature Description
      1. 8.3.1  Isolation
        1. 8.3.1.1 Operation or Functional Isolation
        2. 8.3.1.2 Basic or Enhanced Isolation
        3. 8.3.1.3 Working Voltage
        4. 8.3.1.4 Isolation Voltage Rating
        5. 8.3.1.5 Repeated High-Voltage Isolation Testing
      2. 8.3.2  Power Stage
      3. 8.3.3  Oscillator and Watchdog Circuit
      4. 8.3.4  Thermal Shutdown
      5. 8.3.5  Synchronization
      6. 8.3.6  Light Load Operation (< 10%)
      7. 8.3.7  Load Regulation (10% to 100%)
      8. 8.3.8  Construction
      9. 8.3.9  Thermal Management
      10. 8.3.10 Power-Up Characteristics
    4. 8.4 Device Functional Modes
      1. 8.4.1 Disable and Enable (SYNCIN Pin)
      2. 8.4.2 Decoupling
        1. 8.4.2.1 Ripple Reduction
        2. 8.4.2.2 Connecting the DCV01 in Series
        3. 8.4.2.3 Connecting the DCV01 in Parallel
  9. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Input Capacitor
        2. 9.2.2.2 Output Capacitor
        3. 9.2.2.3 SYNCIN Pin
        4. 9.2.2.4 PCB Design
        5. 9.2.2.5 Decoupling Ceramic Capacitors
        6. 9.2.2.6 Input Capacitor and the Effects of ESR
        7. 9.2.2.7 Ripple and Noise
          1. 9.2.2.7.1 Output Ripple Calculation Example
        8. 9.2.2.8 Dual DCV01 Output Voltage
        9. 9.2.2.9 Optimizing Performance
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Device Nomenclature
    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
  13. 13Mechanical, Packaging, and Orderable Information

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

Decoupling Ceramic Capacitors

All capacitors have losses because of internal equivalent series resistance (ESR), and to a lesser degree, equivalent series inductance (ESL). Values for ESL are not always easy to obtain. However, some manufacturers provide graphs of frequency versus capacitor impedance. These graphs typically show the capacitor impedance falling as frequency is increased (as shown in Figure 9-2). In Figure 9-2, XC is the reactance due to the capacitance, XL is the reactance due to the ESL, and f0 is the resonant frequency. As the frequency increases, the impedance stops decreasing and begins to rise. The point of minimum impedance indicates the resonant frequency of the capacitor. This frequency is where the components of capacitance and inductance reactance are of equal magnitude. Beyond this point, the capacitor is not effective as a capacitor.

GUID-26568367-8AB5-4851-B028-70C21524C43F-low.gifFigure 9-2 Capacitor Impedance versus Frequency

At f0, XC = XL; however, there is a 180° phase difference resulting in cancellation of the imaginary component. The resulting effect is that the impedance at the resonant point is the real part of the complex impedance; namely, the value of the ESR. The resonant frequency must be well above the 800-kHz switching frequency of the device.

The effect of the ESR is to cause a voltage drop within the capacitor. The value of this voltage drop is simply the product of the ESR and the transient load current, as shown in Equation 1.

Equation 1. VIN = VPK – (ESR × ITR)

where

  • VIN is the voltage at the device input
  • VPK is the maximum value of the voltage on the capacitor during charge
  • ITR is the transient load current

The other factor that affects the performance is the value of the capacitance. However, for the input and the full wave outputs (single-output voltage devices), ESR is the dominant factor.