CM109 is a highly integrated single chip USB audio controller specifically for VoIP (Voice over internet protocol) application. All essential analog modules are embedded in CM109, including dual DAC and earphone driver, ADC, microphone booster, PLL, regulator, and USB transceiver. 8 GPIO pins can constitute a 24 key matrix; together with buzzer output pin a concise single chip VoIP application can be achieved. In addition, audio adjustment can be easily controlled via specific HID compliant volume control pins. Many features are easily set with jumper pins. Customized USB VID, PID, and can product string be used for VoIP software authentication. Moreover, individual unique phone number for each device is possible via serial number stored in external EEPROM.

VoIP applications are becoming increasing popular as VoIP can provide free or low-cost calling worldwide. To provide a VoIP experience that is the same as using a regular phone and eliminate the poor call quality that results from using the PC audio, C-Media has developed CM109 USB Controller that enables a regular phone, handset, or headset which is interfaced to the USB port on the PC. With the C-Media OEMs can quickly bring to market a family of low cost high quality VoIP products.

EEPROM write function via Vendor Specific request for Mass Production
Convenience