CM6500B is a USB 2.0 audio chip builds in 8051 for flexible applications. With internal 2-channel ADC and DAC and S/PDIF interface makes it suits for Headset, Docking, Speaker and Mic applications. The internal 8051 can be also developed to a lot of different applications, such as Lync device, iDevice docking or even Android Phone or Tablet/Slate docking device.

CM6500B is compatible with USB audio Class 1.0, thus it can plug & play without additional software installation on the major operation systems. The internal DAC/ADC and S/PDIF out interface support 48K/44.1KHz sampling rate and 16bit resolution.


USB Compliance

  • USB 2.0 full-speed compliant
  • USB Audio Class 1.0 compliant
  • USB Human Interface Device (HID) Class 1.1 compliant
  • Supports USB suspend/resume/reset functions
  • Supports control, interrupt, bulk, and isochronous data transfers

Audio I/O

  • Playback Streams:
    -Stereo DAC
     *Sample Rates: 8K/11.025K/16K/22.05K/32K/44.1K/48K 
     *Supports Bit Length: 16 bit
    -Builds in S/PDIF transmitter 
     *Sample Rates: 44.1K/48K
     *Supports Bit Length: 16 bits
  • Recording Streams:
    -Stereo ADC
     *Sample Rates: 8K/11.025K/16K/22.05K/32K/44.1K/48K
    Supports Bit Length: 16 bits

Integrated 8051 Micro-processor

  • Embedded 8051 micro-processor to handle the comment/protocol transactions
  • Connects to an external EEPROM memory for firmware codes
  • HID interrupts can be implemented via firmware codes
  • Provides maximum HW configuration flexibility with firmware code upgrade
  • VID/PID/Product String can be customized via firmware code programming

Control Interface

  • Master I2C control interface for external audio devices or EEPROM access
  • Max. 14 GPIO pins can be configured via firmware programming
  • GPIOs are configured as HID key and LED indicators


  • Hardware pins for mode configuration including Headset, Speaker, Docking and Mic
  • Hardware pin for A-A path enable/disable
  • Only single 12MHz crystal input is required (embedded PLL function)
  • Single 5V power supply (embedded 5V to 1.8V regulator for digital core, 5V to 3.3V regulator for digital IO, 5V to 3.5V regulator for analog codec)
  • 3.3V digital I/O pads with 5V tolerance
  • Industrial standard LQFP-48 package (7x7mm)
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