C371347_139780418F8DFE40697A24CD62AD2CE5.pdf
CM108B USB Audio Single C hip Datasheet Revision: 1.11 www .cmedia.com.tw P age 1 / 24 Copyright© C -Media Elect ronics Inc. A High ly Integr ated USB Audio Single Chip Regulator 5->3.6, 3.3 & 1.8 USB Interface US…
CM108B
USB Audio Single Chip
Datasheet Revision: 1.11 www.cmedia.com.tw
Page 1 / 24 Copyright© C-Media Electronics Inc.
A Highly Integrated USB Audio Single Chip
Regulator
5->3.6, 3.3 & 1.8
USB
Interface
USB TRX
EEPROM
Interface
RF
PLL
ISO Out
Processing
ISO In
Processing
12M
48M
SPI
USB
DW
DR
SK
CS
USBDP
USBDN
16 bit
DAC
16 bit
DAC
12dB/22dB
Booster
23 ~ -22dB
8 ~ -22dB
0 ~ -45dB
0 ~ -45dB
SRAM
bandgap
VREF
(1.75V)
VREF
VBIAS
(3V)
USB Control
Interface Logics
AREG36
VOLUP
VOLDN
MUTER
MUTEP
LEDO
LEDR
PWRSEL
MODE
MSEL
PDSW
3.6V
LOR
LOL
MICI
N
DREG33
3.3V 1.8V
VREF
LOBS
16 bit
ADC
DREG18
GPIOs
DASCLK/ADSCLK
DALRCK/ADLRCK
DAMCLK/ADMCLK
SDOUT/SDIN
I2S Out/In
BLOCK DIAGRAM
DESCRIPTION
The CM108B is a highly integrated crystal-free USB
audio single chip solution optimized for USB
headset, headphone, and dongle applications. The
CM108B comes with software driver interface
which supports Xear
TM
sound effects for
multimedia entertainments. All essential analog
modules are embedded in the CM108B, including
dual DAC and earphone driver, ADC, microphone
booster, PLL, regulator and USB transceiver
modules. Many features are programmable with
jumper pins or by external EEPROM. Audio
adjustments are easily controlled via specific
HID-compliant volume control pins. An external
codec or audio DSP can be connected to the
CM108B via I2S pin for further processing. Vendors
can customize unique USB VID/PID/Product
String/Manufacture String and min/max/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.
FEATURES
Compliant with USB 2.0 Full Speed Operation
Compliant with USB Audio Device Class
Specification v1.0
Supports USB Suspend/Resume Mode and Remote
Wakeup with Volume Control pins
On-chip oscillator that provides reference sources
for PLL and embedded USB transceiver
Jumper pin for Headset Mode (Playback +
Recording) and Speaker/Headphone Mode
(Playback Only)
Jumper pin for Mixer Unit enable/disable under
Headset Mode and Power Mode setting
I2S interfaces for external CODEC
Anti-pop noise design for plugged and vice-versa
Support Xear
TM
Audio Centre Software Driver for
Windows OS
CM108B
USB Audio Single Chip
Datasheet Revision: 1.11 www.cmedia.com.tw
Page 2 / 24 Copyright© C-Media Electronics Inc.
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
Page 3 / 24 Copyright© C-Media Electronics Inc.
Release notes
Revision
Date
Description
1.00
31 Oct 2013
First release
1.11
18 Nov 2014
Correction on page 6 diagram