What the 48-TQFP package and supply rails demand of the board
The PCM4104PFBT: It requires dual supply rails: a 3 V to 3.6 V analog supply and a separate 5 V digital supply, with the source being both analog and digital — a shared LDO feeding both rails will inject digital switching noise into the analog section unless the layout splits the ground plane under the device.
24-bit resolution at 216k — what that means in the signal chain
24-bit resolution gives a theoretical dynamic range of about 144 dB, but the real noise floor is set by the analog supply cleanliness and the PCB layout — a 10 mV ripple on the 3.3 V rail erases the bottom 6 bits. The 216k samples-per-second ceiling means it handles 96 kHz or 192 kHz audio streams with headroom — at 192 kHz the output filter corner is well above the audio band, so the reconstruction filter design is less aggressive than for a 48 kHz DAC. Four independent DAC channels let it drive a 2.1 or 4.0 audio system from a single IC — each channel has its own voltage-output stage, so the load on one channel does not crosstalk into the others through a shared output buffer.