CM108B Datasheet, PDF (7/24 Pages) C-Media Electronics – A Highly Integrated USB Audio Single Chip

CM108B
USB Audio Single Chip
4.3 Pin signal descriptions
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
Symbol
SPDIFO
DR
DW
SK
CS
MUTER
PWRSEL
DREG18
DREG33
MODE
N.C.
LEDO
GPIO3
DVSS
GPIO4
SDIN
ADSCLK
MUTEP
ADLRCK
ADMCLK
LEDR
ADSEL
TEST
AVSS
VBIAS
VREF
MICIN
N.C.
AVDD
LOL
LOBS
LOR
AVSS
AVDD
DVDD
DVSS
AREG36
Type
DO, 4mA, SR
DI, 8mA, PD, 5VT
DO, 4mA, SR
DO, 4mA, SR
DO, 4mA, SR
DI, ST, PU
DI, ST, PU
P
P
DI, ST, PD
Description
SPDIF output
EEPROM interface data read from EEPROM
EEPROM interface data write to EEPROM
EEPROM interface clock
EEPROM interface chip select
Mute recording (edge trigger with de-bouncing)
Chip power select pin:
H: push up to 3.3V, L: push down to ground
Speaker mode – H: 100mA self-powered, L: 500mA Bus-powered
Headset mode – H: 100mA Bus-powered, L: 500mA Bus-powered
1.8V Regulator Output for Digital Core
3.3V Regulator Output for Digital I/O (driving current 40mA)
Operating mode selection:
H: push up to 3.3V, L: pull down to ground
H: speaker mode - playback only
L: headset mode - playback & recording
DO, SR, 4mA LED operation light: output H for power on, toggling for data transmit
DIO, 8mA, PD, 5VT GPIO pin
P
Digital ground
DIO, 8mA, PD, 5VT GPIO pin
DIO, 8mA, PD, 5VT ADC I2S data input
DO, 2mA, SR ADC I2S serial clock
DI, ST, PU
Mute playback (edge trigger with de-bouncing)
DO, 2mA, SR ADC I2S left/right clock
DO, 2mA, SR
11.2896MHz output for 44.1KHz sampled data and
12.288MHz output for 48KHz sampled data
DO, SR, 4mA LED for mute recording indicator, output H when recording is muted
ADC input source select pin
DI, ST, PD
H: use external (via I2S) ADC
L: use internal ADC
(H: push up to 3.3V, L: push down to ground)
Test mode select pin,
DI, ST, PD
H: test mode
L: normal operation
(H: push up to 3.3V, L: push down to ground)
P
Analog ground
AO
Microphone bias voltage supply (3V), with a small driving capability
AO
Connecting to external decoupling capacitor for embedded bandgap
circuit, 1.75V output
AI
Microphone input, input impedance is 10k Ohm
P
5V analog power for analog circuit
AO
Line out: left channel
AO
DC 1.75V output for line out bias
AO
Line out: right channel
P
Analog ground
P
5V power supply for analog circuit
P
5V power supply for internal regulator
P
Digital ground
P
3.6V analog power for analog circuit
Datasheet Revision: 1.11
Page 7 / 24
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