TAS5615 oscillation

LC filters for TI's class-D audio power amplifiers (APAs) are designed for very low losses, to maintain high efficiency.  This makes their Q's very high, so they can ring when the audio output of the APA includes significant transients, as in clipping or square-wave amplification.  

This ringing is not a form of oscillation, implying instability in the APA.  TI's APAs are designed for low output impedance and high stability regardless of load.

The ringing appears as a damped sinusoid at the characteristic frequency of the LC filter.  It begins at the onset and the end of clipping, where clipping creates sharp discontinuities in the audio output.  It also begins on the edge of any square wave transition or similar transient.  Generally it is not serious with a normal load.  These transients can be expected to generate higher ringing when there is no load.