CM108: USB Audio Solution

As one of the Integrated circuits part, CM108 is a highly integrated single chip USB audio solution. All essential analog modules are embedded in CM108, including dual DAC and earphone driver, ADC, microphone booster, PLL, regulator, and USB transceiver. It is very suitable for USB headset, USB earphone or USB audio interface box application. Many features are programmable with jumper pins or external EEPROM. In addition, audio adjustment can be easily controlled via specific HID compliant volume control pins. For value added application, external codec or audio DSP can be connected to CM108 via I²S pin for further processing. 4 GPIO pins can be accessed with customer application software for additional value added application.

FEATURES for such IC part: 

1. Compliant with USB 2.0 Full Speed Operation

2. Compliant with USB Audio Device Class Specification v1.0

3. Supports USB Suspend / Resume Mode and Remote Wakeup with Volume Control Pins

4. Single 12MHz Crystal Input with On-chip PLL and Embedded USB Transceiver

5. Jumper Pin for Speaker Mode (Playback Only) or Headset Mode (Playback + Recording)

6. For Headset Mode, USB Audio Function Topology has 2 Input Terminals, 2 Output Terminals, 1 Mixer Unit, 1 Selector Unit, and 3 Feature Units

7. Jumper Pin for Mixer Unit Enable / Disable under Headset Mode

8. For Speaker Mode, USB Audio Function  Topology has 1 Input Terminal, 1 Output Terminal, and 1 Feature Unit

9. Support One Control Endpoint, One Isochronous Out Endpoint, One Isochronous In Endpoint, and One Interrupt In Endpoint

10. Alternate Zero Bandwidth Setting for Releasing Playback Bandwidth on USB Bus w

this Device is Inactive

11. Supports AES/EBU, IEC60958, S/PDIF Consumer Formats for Stereo PCM Da

S/PDIF Output

12. Volume Up, Volume Down, and Playback Mute Pins support USB HID device clas

Host Control Synchronization

13. Record Mute Pin with LED Indicator for Record Mute Status

14. External EEPROM Interface for Vendor Specific USB VID, PID, and Serial Numbe

15. EEPROM Write Function via Vendor Specific request for Mass Produ

Convenience

16. Customized Embedded VID, PID, and Product String by Customer Request

17. 4 GPIO Pins with Read/Write via HID Interface

18. Jumper Pin to Set the Output Voltage Swing (3.5V or 2.5V)

19. Jumper Pin to Set the Power Mode (100mA or 500mA, Bus Power or Self Power)

20. Isochronous Transfer uses Adaptive Mode with Internal PLL for Synchronization

21. 48K / 44.1KHz Sampling Rate for Both Playback and Recording

22. Soft Mute Function