SLOA339 July   2024 TAS2764 , TAS2764 , TAS2780 , TAS2780 , TAS2781 , TAS2781

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Capacitor Only Connected at the Class-D Outputs
    2. 1.2 LC Filter Connected at the Class-D Outputs
    3. 1.3 Ferrite Bead Filters
  5. 2EMI Filter Considerations
    1. 2.1 Impedance Consideration of EMI Filter
    2. 2.2 Device Reliability Constraint for High Output Voltage
    3. 2.3 EMI Filter Current Reliability
  6. 3Post Filter Feedback
  7. 4Loop Stability With Post Filter Feedback
  8. 5User Guide: EMI Filter Modeling and Post Filter Feedback Validation Tool
  9. 6Summary
  10. 7References

2.2 Device Reliability Constraint for High Output Voltage

While using an EMI filter the device pin VSNS voltage can overshoot beyond OUTP and can theoretically go up to as high as twice the voltage. For example, the maximum PVDD voltage TAS2764 is 16V, which means the VSNS can overshoot to 32V. TI recommends that if the voltage overshoot at VSNS goes beyond 30V in TAS2764 and 40V in TAS2780, 81, 83, is mandatory that an external resistor of (easily available) 1KΩ, 4.7KΩ can be connected in series before connecting the feedback from speaker to VSNSP and VSNSM. This is required to limit the current through the device internal ESD cell on the VSNS pin, which activates to clamp due to high voltage ringing at the speaker node.