SLOS993A March   2018  – June 2018 TPA3138D2

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
      2.      TPA3138 Layout with Ferrite Beads
  4. 4 Revision History
  5. 5 Device Comparison Table
  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
    6. 7.6 Switching Characteristics
    7. 7.7 Typical Characteristics
  8. 8 Parameter Measurement Information
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1  Analog Gain
      2. 9.3.2  SD/FAULT Operation
      3. 9.3.3  PLIMIT
      4. 9.3.4  Spread Spectrum and De-Phase Control
      5. 9.3.5  GVDD Supply
      6. 9.3.6  DC Detect
      7. 9.3.7  PBTL Select
      8. 9.3.8  Short-Circuit Protection and Automatic Recovery Feature
      9. 9.3.9  Over-Temperature Protection (OTP)
      10. 9.3.10 Over-Voltage Protection (OVP)
      11. 9.3.11 Under-Voltage Protection (UVP)
    4. 9.4 Device Functional Modes
      1. 9.4.1 MODE_SEL = LOW: BD Modulation
      2. 9.4.2 MODE_SEL = HIGH: Low-Idle-Current 1SPW Modulation
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Applications
      1. 10.2.1 Design Requirements
        1. 10.2.1.1 PCB Material Recommendation
        2. 10.2.1.2 PVCC Capacitor Recommendation
        3. 10.2.1.3 Decoupling Capacitor Recommendations
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Ferrite Bead Filter Considerations
        2. 10.2.2.2 Efficiency: LC Filter Required with the Traditional Class-D Modulation Scheme
        3. 10.2.2.3 When to Use an Output Filter for EMI Suppression
        4. 10.2.2.4 Input Resistance
        5. 10.2.2.5 Input Capacitor, Ci
        6. 10.2.2.6 BSN and BSP Capacitors
        7. 10.2.2.7 Differential Inputs
        8. 10.2.2.8 Using Low-ESR Capacitors
      3. 10.2.3 Application Performance Curves
        1. 10.2.3.1 EN55013 Radiated Emissions Results
        2. 10.2.3.2 EN55022 Conducted Emissions Results
  11. 11Power Supply Recommendations
    1. 11.1 Power Supply Decoupling, CS
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Third-Party Products Disclaimer
    2. 13.2 Documentation Support
      1. 13.2.1 Related Documentation
    3. 13.3 Receiving Notification of Documentation Updates
    4. 13.4 Community Resources
    5. 13.5 Trademarks
    6. 13.6 Electrostatic Discharge Caution
    7. 13.7 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • PWP|28
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9.3.3 PLIMIT

If selected, the PLIMIT operation limits the output voltage level to a voltage level below the supply rail. If the amplifier operates like it is powered by a lower supply voltage, then it limits the output power by voltage clipping. Add a resistor divider from GVDD to ground to set the threshold voltage at the PLIMIT pin.

TPA3138D2 Plimit.gifFigure 17. PLIMIT Circuit Operation

The PLIMIT circuit sets a limit on the output peak-to-peak voltage. The limiting is done by limiting the duty cycle to a fixed maximum value. The limit can be thought of as a "virtual" voltage rail which is lower than the supply connected to PVCC. The "virtual" rail is approximately 5.7 times (with BD mode) and 11.4 times (with 1SPW mode) the voltage at the PLIMIT pin. The output voltage can be used to calculate the maximum output power for a given maximum input voltage and speaker impedance.

Equation 1. TPA3138D2 EQ1_Pout_los708.gif

where

  • POUT (10%THD) = 1.25 × POUT (unclipped)
  • RL is the load resistance.
  • RS is the total series resistance including RDS(on), and output filter resistance.
  • VP is the peak amplitude, which is limited by "virtual" voltage rail.