CM118B Datasheet, PDF (1/25 Pages) C-Media Electronics – Highly Integrated & Configurable USB Audio Single Chip

CM118B
Highly Integrated & Configurable USB Audio Single Chip
DESCRIPTION
The CM118B is a highly integrated, crystal-less USB
audio single chip solution optimized for USB
headset, headphone, dongle, microphone and
application such as VoIP (voice over Internet
protocol). All essential analog modules are
embedded in the CM118B, including dual DAC and
ADC, earphone driver, microphone booster, PLL,
regulator, and USB transceiver. It also supports 3
GPIO pins. In addition, audio adjustment can be
easily controlled via specific HID compliant volume
control pins. Many features such as headset,
headphone and microphone only topologies are
programmable with jumper pins. Vender can
customize unique USB VID / PID / Product String /
Manufacture String and min/max/initial volumes to
the external EEPROM. The CM118B also offers
anti-pop noise circuits design and internal oscillator
which can operate without an external crystal
oscillator.
BLOCK DIAGRAM
FEATURES
 Compliant with USB 2.0 Full Speed Operation
 Compliant with USB Audio Device Class v1.0
 Supports USB Suspend/Resume Mode and Remote
Wakeup with Volume Control pins
 On-chip oscillator to provide reference sources for
PLL and embedded USB transceiver
 Jumper pin for Headset Mode (Playback +
Recording), Microphone Mode (Stereo and Mono
Recording),or Speaker/Headphone Mode
(Playback Only)
 Jumper pin for Mixer Unit enable/disable under
Headset Mod, and Power Mode setting
 I2C interface to access internal registers, and I2S
Output for external DAC
 In Headset Mode, USB audio function topology has
2 Input Terminals, 2 Output Terminals, 1 Mixer
Unit, 1 Selector Unit, and 3 Feature Units
 In Speaker Mode, USB audio function topology has
1 Input Terminal, 1 Output Terminal, and 1
Feature Unit.
 In Microphone Mode, USB audio function topology
has 1 Input Terminal, 1 Output Terminal, 1
Selector Unit and 1 Feature Unit.
 Anti-pop noise design for plug and unplug.
PWRSEL
MODE
AREG36 DREG33 DREG18 PDSW MSEL
3.6V 3.3V 1.8V
Regulator
5->3.6, 3.3 & 1.8
DW
DR _SPI
SK
CS
EEPROM
Interface
USBDP
USBDN
USB
USB TRX
USB
Interface
RF
PLL
48M
12M
VOLUP
DASCLK
VOLDN
DALRCK
MUTER LEDO
SCLK DAMCLK
MUTEP LEDR GPIOs SDAT SDOUT
I2C I2S Out
Interface Logics
USB Control
ISO Out
Processing
VRE
F
16 bit
DAC
0 ~ -37dB
16 bit
DAC
0 ~ -37dB
SRAM
8 ~ -22dB
ISO In
Processing
16 bit
ADC
12dB/22dB
23 ~ -22dB
Booster
8 ~ -22dB
16 bit
ADC
VREF
23 ~ -22dB
12dB/22dB
Booster
bandgap
LOBS
LOR
LOL
MICINR
MICINL
VREF
(1.75V)
VBIAS
(3V)
Datasheet Revision: 1.00
Page 1 / 25
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