This part is a kind of semiconductor called CM6631.

Function of this product has USB 2.0 High-Speed True HD Audio Processor.

Manufacturers : C-Media

Image and pinout :

Some of the text within the PDF file :

CM6631 USB 2.0 High-Speed True HD Audio Processor DESCRIPTION Cmedia CM6631 is the world’s first USB2.0 true high-speed audio processor that can support the latest USB Audio Device Class Definition V2.0 and high-definition audio processing capability up to 192KHz/32bit. CM6631 provides the industrial standard I2S and HDA audio interface and also integrates 192KHz/24bit S/PDIF transmitter/receiver and MIDI I/O device. It’s suitable for versatile, high-profile, typical 2-channel I/O audio applications. Furthermore, CM6631 has an embedded 8051 microprocessor that can enhance the best flexibility and functionality with external upgradeable F/W codes. CM6631 would be the most high-fidelity and powerful audio core for high-value USB2.0 audio products. FEATURES  USB Spec. Rev.2.0 high-sp [ ... ]

CM6631 PDF Datasheet Download