LC filter selection recommendation principles show as below::

1. Make sure f_Resonance > 25 kHz for over current avoidance and peaking voltage protection. The Max inductance of Inductor is limited by the f_Resonance > 25 kHz. f_Resonance = 1/(2×π×(L×(C+2×C_piezo))^0.5)
2. Larger inductor means larger DCR (better stability) and smaller startup/ripple current.
3. Larger inductor, smaller f_Resonance, more loop gain margin, better stability.
4. Some corner consideration:
   • Inductor variation and DCR variation. Suggest to keep within +/-10% make sure f_Resonance > 25 kHz.
   • Make sure DCR of inductor larger than 25 mΩ.
   • Piezo speaker capacitance variation. Also make sure f_Resonance > 25 kHz.
   Table 9-1 LC Filter recommendation

   Piezo Speaker Capacitance	Fsw (Switching Frequency)	Class D Loop Bandwidth (kHz)	LC Filter Recommendation	Resonance Frequency
   0.6 μF	768kHz	175kHz	8.2 μH (DCR ≥ 25 m?) +0.47 μF	43.4 kHz
   			10 μH (DCR ≥ 25 m?) + 0.68 μF	36.9 kHz
   			15 μH (DCR ≥ 25 m?) + 0.47 μF	32 kHz
   			22 μH (DCR ≥ 25 m?) + 0.4 7μF	26.4 kHz
   1 μF			8.2 μH (DCR ≥ 25 m?) +0.47 μF	35.1 kHz
   			10 μH (DCR ≥ 25 m?) + 0.68 μF	30.5 kHz
   			15 μH (DCR ≥ 25 m?) + 0.47 μF	26 kHz
   2 μF			4.7 μH (DCR ≥ 25 m?) +0.47 μF	34.7 kHz
   			8.2 μH (DCR ≥ 25 m?) +0.47 μF	26.3 kHz
   4.5 μF			3.3 μH (DCR ≥ 25 m?) +0.47 μF	28 kHz