WM8974GEFL/V Wolfson Microelectronics, WM8974GEFL/V Datasheet - Page 63

• Manufacturer Part Number: WM8974GEFL/V
• Description: Audio CODECs Mono Codec with Spkr
• Manufacturer: Wolfson Microelectronics

Specifications of WM8974GEFL/V

• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: QFN-24
• Minimum Operating Temperature: - 25 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Production Data
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POWER MANAGEMENT
SAVING POWER BY REDUCING OVERSAMPLING RATE
Table 59 ADC and DAC Oversampling Rate Selection
VMID
Table 60 VMID Impedance Control
BIASEN
Table 61 BIASEN Control
ESTIMATED SUPPLY CURRENTS
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.
The analogue circuitry will not work when VMID is disabled (VMIDSEL[1:0] = 00b). 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.
When either the DAC or ADC are enabled it is estimated that approximately 4mA 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 an additional 700 microamps will be drawn from DCVDD.
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
00
0
DEFAULT
DEFAULT
0
0
DEFAULT
Reference string impedance to VMID
pi uxiliary nes startup time):
00=off (open circuit)
01=50k Ω
10=500k Ω
11=5k Ω (for fastest startup)
Analogue amplifier bias control
0=Disabled
1=Enabled
DAC oversample rate select
0 = 64x (lowest power)
1 = 128x (best SNR)
ADC oversample rate select
0 = 64x (lowest power)
1 = 128x (best SNR)
PD, Rev 4.5, September 2008
DESCRIPTION
DESCRIPTION
DESCRIPTION
WM8974
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