[Verified] USB Type-C sound card DAC is based on PCM2912A CODEC

Type-C small sound card based on PCM2912A, with on-board linear power supply and an LM4808 headphone amplifier. It has been welded and verified that it can be used normally, and the mobile phone and computer have tested OK.
PCM2912A is an integrated USB-CODEC chip from TI that supports up to 16bit 48000Hz. The parameters don’t seem to be particularly high, but in fact, for playback, they have reached the upper limit of human hearing and are considered sufficient. The advantage of this chip is that it does not require a dedicated USB-I2S bridge and is not too expensive.
The problem with USB power supply is that no one knows how much ripple there is at the interface end and whether the power supply is stable. This DAC uses a method of first boosting the voltage to 6.3V and then using an LDO to reduce it back to 5V to make the power supply cleaner.
You can still hear a small amount of background noise when wearing headphones, maybe the isolation of the analog part of the board is not good enough.
 
Sometimes the TVS tube (D2) doesn't work after welding it, and I don't know why. However, it does not affect normal use without welding.
If you think the light is too bright, the LED current limiting resistor can be larger, such as 1k-5k or even higher, it is no problem.
The microphone is not heat-resistant, so be sure to leave it until last.