wm8982gefl-v Wolfson Microelectronics plc, wm8982gefl-v Datasheet - Page 80

• Manufacturer Part Number: wm8982gefl-v
• Description: Mono Codec With Speaker Driver And Video Buffer
• Manufacturer: Wolfson Microelectronics plc

WM8982
POWER MANAGEMENT
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SAVING POWER BY REDUCING OVERSAMPLING RATE
The default mode of operation of the ADC and DAC digital filters is in 64x oversampling mode. Under
the control of ADCOSR and DACOSR the oversampling rate may be doubled. 64x oversampling
results in a slight decrease in noise performance compared to 128x but lowers the power
consumption of the device.
Table 64 ADC and DAC Oversampling Rate Selection
VMID
The analogue will not work unless VMID is enabled (VMIDSEL≠00). The impedance of the VMID
resistor string, together with the decoupling capacitor on the VMID pin will determine the startup time
of the VMID circuit.
Table 65 VMID Impedance Control
BIASEN
The analogue amplifiers will not operate unless BIASEN is enabled.
Table 66 Analogue Bias Control
ESTIMATED SUPPLY CURRENTS
When either the DAC or ADC are enabled approximately 7mA will be drawn from DCVDD when
DCVDD=1.8V and fs=48kHz (This will be lower at lower sample rates). When the PLL is enabled
approximately 1.5mA additional current will be drawn from DCVDD. The video buffer will draw about
4mA with no load attached, in normal operating up to 30 mA will be drawn.
R10
DAC control
R14
ADC control
R1
Power
management 1
R1
Power
management 1
REGISTER
ADDRESS
REGISTER
REGISTER
ADDRESS
ADDRESS
3
3
1:0
3
BIT
BIT
BIT
VMIDSEL
BIASEN
LABEL
LABEL
DACOSR128
ADCOSR128
LABEL
0
DEFAULT
00
DEFAULT
DEFAULT
Analogue amplifier bias control
0=disabled
1=enabled
0
0
Reference string impedance to VMID pin
(detemines startup time):
00=off (open circuit)
01=75kΩ
10=300kΩ
11=5kΩ (for fastest startup)
DAC oversample rate select
0 = 64x (lowest power)
1 = 128x (best SNR)
ADC oversample rate select
0 = 64x (lowest power)
1 = 128x (best SNR)
DESCRIPTION
PP, Rev 3.2, September 2008
DESCRIPTION
DESCRIPTION
Pre-Production
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