wm8941 Wolfson Microelectronics plc, wm8941 Datasheet - Page 73

• Manufacturer Part Number: wm8941
• Description: Mono Codec With Speaker Driver And Video Buffer
• Manufacturer: Wolfson Microelectronics plc

Production Data
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POWER MANAGEMENT
VMID
Table 58 VMID Impedance Control
BIASEN
Table 59 BIASEN Control
ESTIMATED SUPPLY CURRENTS
Table 60 AVDD Supply Current
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
start-up time of the VMID circuit.
When either the DAC or ADC are enabled it is estimated that approximately 4mA will be drawn from
DVDD when fs=48kHz (This will be lower at lower sample rates). When the PLL is enabled an
additional 700 microamps will be drawn from DVDD.
Table 60 shows the estimated 3.3V AVDD current drawn by various circuits, by register bit.
R1
Power
management 1
R1
Power
management 1
MONOEN
PLLEN
MICBEN
BIASEN
BUFIOEN
VMIDSEL
BOOSTEN
INPPGAEN
ADCEN
MONOEN
SPKPEN
SPKNEN
MONOMIXEN
SPKMIXEN
DACEN
REGISTER BIT
REGISTER
REGISTER
ADDRESS
ADDRESS
1:0
3
0.2mA
1.4mA (with clocks applied)
0.5mA
0.3mA
0.1mA
5K=>0.3mA, less than 0.1mA for 50k/250k
0.2mA
0.2mA
2.6mA
0.2mA
1mA from SPKVDD
1mA from SPKVDD
0.2mA
0.2mA
1.8mA
BIT
BIT
VMIDSEL 00
BIASEN
LABEL
LABEL
AVDD CURRENT (MILLIAMPS)
0
DEFAULT
DEFAULT
Reference string impedance to VMID pin
(determines startup time):
00=off (open circuit)
01=50kΩ
10=250kΩ
11=5kΩ (for fastest startup)
Analogue amplifier bias control
0=Disabled
1=Enabled
DESCRIPTION
DESCRIPTION
PD, Rev 4.0, August 2008
WM8941
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