INTRODUCTION

CM6400 is an advanced highly-integrated USB audio single chip optimized for featured USB headset or other audio applications. CM6400 integrates 5-band hardware digital equalizer (EQ) processing unit with up-to-4 presets to fit different applications or improve headphone SPL characteristics. In addition, embedded Mic Auto-Gain-Control (AGC) and clipping-protection functionality could automatically adjust variant sound input scale to get rid of large signal clipping and also get more constant recording level during voice communication. With outstanding SNR/THD audio performance overtaking WHQL standard and its versatile HW functions, CM6400 is the ideal all-in-one USB headset chip that could empower and differentiate your product ideas at your own will.

PRODUCT FEATURES
USB Compliance

USB spec. 2.0 full-speed compatible and USB-IF certification
USB audio device class spec. 1.0 compliant
USB HID device class spec. 1.1 compliant
Architecture

USB suspend/resume support
Embedded USB transceiver and power-on reset circuit
Single 12MHz Crystal Input with On-chip PLL
Serial 24C02 EEPROM programming interface supported for customizing VID/PID/Product String/ Manufacture String/Serial Number/Volume Range/Initial Volume/HID_Disable/EQ/AGC and other configuration
Integrates 5-Band Hardware Equalizer with up-to-4 preset modes  (00_Default/Music, 11_Movies , 01_Gaming, 10_Communication,) selectable by 2 HW control pins and the gain value of each band could be customized by EEPROM parameters
Built-in Automatic Gain Control (AGC) for microphone recording (Enabled by EEPROM)
MCU / EEPROM / GPIO control via HID / Vender command interface (MCU read/write support 16 bytes data transfer bandwidth)
Supports up to 7 GPIO pins (Configured by EEPROM)
USB Bus-Power mode with High-power (500mA) and Low-power (100mA, default) mode options by external selection pin
Single 5V power supply with embedded 5V-to-4.5V and 5V-to-3.3V regulators
Audio I/O

2-channel DAC outputs with 16-ohms headphone amplifier (supports 16-bit resolution and 48KHz, 44.1KHz, 32KHz, 22.05KHz, 16KHz, 11.025KHz, 8KHz sampling rates; note only 48K & 44.1KHz are available when EQ function is enabled.)
2-channel ADC inputs (supports 16-bit resolution and 48KHz, 44.1KHz, 32KHz, 22.05KHz, 16KHz, 11.025KHz, and 8KHz sampling rates; note only 48K & 44.1KHz are available when EQ function is enabled.)
Supports stereo mic inputs with independent voltage bias pins and analog mixer (monitoring) function
Supports ADC DC offset cancellation high-pass-filter
Supports optional digital S/PDIF output (up to 48KHz/16bit) compatible with AES/EBU IEC-60958 spec. (default on, but not reported in USB audio descriptor)
Configurable USB audio topology to Headset/Speaker/Microphone modes by EEPROM
Control Interfaces

Featured with Microsoft® HID controls including Vol_Up / Vol_Dn / Playback_Mute / Record_Mute / Play_Pause / Stop / Previous / Next hot-key buttons (enabled by default)
Optional analog DC VR volume control pin with internal ADC potentiometer
I2C master/slave mode control interface
Supports 4 LED indicator control pins: Operation status/ Playback_Mute /Recording_Mute (Enabled by default) / Mic Clipping-Detection (enabled by EEPROM)
General

Industrial standard small footprint LQFP-48 green package
Plug & Play for OS supports standard USB audio class 1.0 device driver

BLOCK DIAGRAM