C371347_139780418F8DFE40697A24CD62AD2CE5.pdf - 第3页

CM108B

USB Audio Single Chip

Datasheet Revision: 1.11 www.cmedia.com.tw

TABLE OF CONTENTS

1 Description and overview ......................................................................... 4

2 Ordering information .............................................................................. 4

3 Features ............................................................................................. 4

4 Pin descriptions ..................................................................................... 6

4.1 Pin assignment by pin number ............................................................... 6

4.2 Pin-out diagram ................................................................................ 6

4.3 Pin signal descriptions ........................................................................ 7

5 Block diagram ....................................................................................... 9

6 I2S Interface ...................................................................................... 10

7 Function description ............................................................................. 11

7.1 USB interface ................................................................................. 11

7.1.1 USB audio topology diagram for headset ..................................... 11

7.1.2 USB audio topology diagram for speaker ..................................... 12

7.1.3 Content format for EEPROM (93C46) .......................................... 13

7.1.4 EEPROM SPI interface timing information .................................... 14

7.2 Jumper pins and mode setting: ............................................................ 15

7.2.1 Mode pin and msel pin .......................................................... 15

7.2.2 Mode pin and pwrsel pin ........................................................ 15

7.3 HID feature .................................................................................... 16

7.3.1 HID descriptors ................................................................... 16

7.4 Internal Registers ............................................................................. 17

8 Electrical characteristics ........................................................................ 20

8.1 Absolute maximum rating ................................................................... 20

8.2 Operation conditions ......................................................................... 20

8.3 Electrical parameters ........................................................................ 20

9 Package information ............................................................................. 22

Reference ............................................................................................... 23

CM108B

USB Audio Single Chip

Datasheet Revision: 1.11 www.cmedia.com.tw

Release notes

Revision

Date

Description

1.00

31 Oct 2013

First release

1.11

18 Nov 2014

Correction on page 6 diagram

CM108B

USB Audio Single Chip

Datasheet Revision: 1.11 www.cmedia.com.tw

1 Description and overview

The CM108B is a highly integrated single-chip USB audio solution. All essential analog modules are embedded in the

CM108B, including dual DAC and earphone driver, ADC, microphone booster, PLL, regulator and USB transceiver

modules. It is perfectly suited to USB headset, USB earphone or USB audio-interface box applications. As well, many

features are programmable with jumper pins or by external EEPROM.

The CM108B can connect to an external codec or audio DSP via I2S pins for further processing. Plus, 3 GPIO pins can

be accessed with customer application software for additional value-adding applications. In addition, audio

adjustments can be easily controlled via specific HID compliant volume control pins. Many features are

programmable with jumper pins or external EEPROM. Vendors can customize unique USB VID/PID/Product

String/Manufacture String and max/min/initial volumes to EEPROM. The CM108B also comes with an anti-pop noise

circuits design and internal oscillator which can operate without an external crystal oscillator.

2 Ordering information

Model No.

Package

Operating Ambient

Temperature

Supply Range

CM108B

48-pin LQFP, 7mm × 7mm × 1.4mm

(plastic)

-20°C to +70°C

DVdd = 5V, AVdd = 5V

3 Features

 Supports USB 2.0 full speed operation

 Compliant with USB audio device class specification 1.0

 Supports USB suspend/resume modes and remote wakeup with volume control pins

 On-chip oscillator that provides reference sources for PLL and embedded USB transceiver

 Support Xear

TM

audio driver for multimedia sound effects in Windows OS, for further information please refer to

CM108B Xear

TM

Audio Center Driver User’s Manual

 Jumper pin for speaker mode (playback only) or headset mode (playback plus recording)

 For headset mode, USB audio function topology has 2 input terminals, 2 output terminals, 1 mixer unit, 1 selector

unit and 3 feature units

 Jumper pin allows for mixer unit enable/disable when in headset mode

 For speaker mode, the USB audio topology has 1 input terminal, 1 output terminal and 1 feature unit

 Supports one control endpoint, one isochroous OUT endpoint, one isochroous IN endpoint, and one interrupt IN

endpoint

 Alternate zero bandwidth setting for releasing playback bandwidth on USB Bus when device is inactive

 Anti-pop noise design for device plugged and vice-versa, while A-A path is off

 Supports AES/EBU, IEC60958, S/PDIF consumer formats for stereo PCM data at S/PDIF output

 Volume up, volume down, and playback mute pins support USB HID for host control synchronization

 Record mute pin with LED indicator for record mute status

 Includes external EEPROM Interface for Vendor Specific USB VID, PID, Product String, Manufacture String, and

max/min/initial volumes

 3 GPIO pins with read/write via HID interface

 Jumper pin to set the power mode (100mA or 500mA, Bus-powered or self-powered)

 Isochronous transfer uses adaptive mode with internal PLL for synchronization

 48K/44.1KHz sampling rate for both playback and recording

 Soft mute function