ZHCS891G April   2012  – December 2017 TPA3116D2 , TPA3118D2 , TPA3130D2

PRODUCTION DATA.  

  1. 特性
  2. 应用
  3. 说明
    1.     Device Images
      1.      简化应用电路
  4. 修订历史记录
  5. Pin Configuration and Functions
    1.     Pin Functions
  6. Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 DC Electrical Characteristics
    6. 6.6 AC Electrical Characteristics
    7. 6.7 Typical Characteristics
  7. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Gain Setting and Master and Slave
      2. 7.3.2  Input Impedance
      3. 7.3.3  Startup and Shutdown Operation
      4. 7.3.4  PLIMIT Operation
      5. 7.3.5  GVDD Supply
      6. 7.3.6  BSPx AND BSNx Capacitors
      7. 7.3.7  Differential Inputs
      8. 7.3.8  Device Protection System
      9. 7.3.9  DC Detect Protection
      10. 7.3.10 Short-Circuit Protection and Automatic Recovery Feature
      11. 7.3.11 Thermal Protection
      12. 7.3.12 Device Modulation Scheme
        1. 7.3.12.1 MODSEL = GND: BD-Modulation
        2. 7.3.12.2 MODSEL = HIGH: 1SPW-modulation
      13. 7.3.13 Efficiency: LC Filter Required with the Traditional Class-D Modulation Scheme
      14. 7.3.14 Ferrite Bead Filter Considerations
      15. 7.3.15 When to Use an Output Filter for EMI Suppression
      16. 7.3.16 AM Avoidance EMI Reduction
    4. 7.4 Device Functional Modes
      1. 7.4.1 Mono Mode (PBTL)
  8. Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Select the PWM Frequency
        2. 8.2.2.2 Select the Amplifier Gain and Master/Slave Mode
        3. 8.2.2.3 Select Input Capacitance
        4. 8.2.2.4 Select Decoupling Capacitors
        5. 8.2.2.5 Select Bootstrap Capacitors
      3. 8.2.3 Application Curves
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Heat Sink Used on the EVM
  11. 11器件和文档支持
    1. 11.1 相关链接
    2. 11.2 接收文档更新通知
    3. 11.3 社区资源
    4. 11.4 商标
    5. 11.5 静电放电警告
    6. 11.6 Glossary
  12. 12机械、封装和可订购信息

Ferrite Bead Filter Considerations

Using the Advanced Emissions Suppression Technology in the TPA3116D2 amplifier it is possible to design a high efficiency class-D audio amplifier while minimizing interference to surrounding circuits. It is also possible to accomplish this with only a low-cost ferrite bead filter. In this case it is necessary to carefully select the ferrite bead used in the filter. One important aspect of the ferrite bead selection is the type of material used in the ferrite bead. Not all ferrite material is alike, so it is important to select a material that is effective in the 10 to 100 MHz range which is key to the operation of the class-D amplifier. Many of the specifications regulating consumer electronics have emissions limits as low as 30 MHz. It is important to use the ferrite bead filter to block radiation in the 30 MHz and above range from appearing on the speaker wires and the power supply lines which are good antennas for these signals. The impedance of the ferrite bead can be used along with a small capacitor with a value in the range of 1000 pF to reduce the frequency spectrum of the signal to an acceptable level. For best performance, the resonant frequency of the ferrite bead/ capacitor filter should be less than 10 MHz.

Also, it is important that the ferrite bead is large enough to maintain its impedance at the peak currents expected for the amplifier. Some ferrite bead manufacturers specify the bead impedance at a variety of current levels. In this case it is possible to make sure the ferrite bead maintains an adequate amount of impedance at the peak current the amplifier will see. If these specifications are not available, it is also possible to estimate the bead current handling capability by measuring the resonant frequency of the filter output at low power and at maximum power. A change of resonant frequency of less than fifty percent under this condition is desirable. Examples of ferrite beads which have been tested and work well with the TPA3130D2 can be seen in the TPA3130D2EVM user guide SLOU341.

A high quality ceramic capacitor is also needed for the ferrite bead filter. A low ESR capacitor with good temperature and voltage characteristics will work best.

Additional EMC improvements may be obtained by adding snubber networks from each of the class-D outputs to ground. Suggested values for a simple RC series snubber network would be 18 Ω in series with a 330 pF capacitor although design of the snubber network is specific to every application and must be designed taking into account the parasitic reactance of the printed circuit board as well as the audio amp. Take care to evaluate the stress on the component in the snubber network especially if the amp is running at high PVCC. Also, make sure the layout of the snubber network is tight and returns directly to the GND pins on the IC.

TPA3116D2 TPA3118D2 TPA3130D2 No85_los708.gifFigure 34. TPA311xD2 Radiated Emissions