wm8952 Wolfson Microelectronics plc, wm8952 Datasheet - Page 53

• Manufacturer Part Number: wm8952
• Description: Mono Adc With Microphone Pre-amplifier
• Manufacturer: Wolfson Microelectronics plc

Pre Production
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POWER MANAGEMENT
VMID
Table 43 VMID Impedance Control
BIASEN
Table 44 BIASEN Control
ESTIMATED SUPPLY CURRENTS
Table 45 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 ADC is 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 45 shows the estimated 3.3V AVDD current drawn by various circuits, by register bit.
R1
Power
management 1
R1
Power
management 1
PLLEN
MICBEN
BIASEN
BUFIOEN
VMIDSEL
BOOSTEN
INPPGAEN
ADCEN
REGISTER BIT
REGISTER
REGISTER
ADDRESS
ADDRESS
1:0
3
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
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
PP, Rev 3.0, December 2008
WM8952
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