WM8976GEFL/V Wolfson Microelectronics, WM8976GEFL/V Datasheet - Page 27

• Manufacturer Part Number: WM8976GEFL/V
• Description: Audio CODECs Mono ADC Stereo DAC with Spkr
• Manufacturer: Wolfson Microelectronics

Specifications of WM8976GEFL/V

• Mounting Style: SMD/SMT
• Package / Case: QFN-32
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Production Data
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Table 8 Input BOOST Stage Control
Table 9 Input BOOST Enable Control
MICROPHONE BIASING CIRCUIT
Table 10 Microphone Bias Enable Control
Table 11 Microphone Bias Voltage Control
The BOOST stage is enabled under control of the BOOSTEN register bit.
The MICBIAS output provides a low noise reference voltage suitable for biasing electret type
microphones and the associated external resistor biasing network. Refer to the Applications
Information section for recommended external components. The MICBIAS voltage can be altered via
the MBVSEL register bit.
MICBIAS=0.65*AVDD. The output can be enabled or disabled using the MICBEN control bit.
The internal MICBIAS circuitry is shown in Figure 16.
capability for MICBIAS is 3mA. The external biasing resistors therefore must be large enough to limit
the MICBIAS current to 3mA.
R47
Input BOOST
control
R2
Power
management
2
R1
Power
management 1
R44
Input control
REGISTER
REGISTER
REGISTER
ADDRESS
ADDRESS
ADDRESS
REGISTER
ADDRESS
2:0
6:4
4
8
BIT
BIT
BIT
4
BIT
AUXL2BOOSTVOL
L2_2BOOSTVOL
BOOSTENL
MBVSEL
LABEL
LABEL
MICBEN
When MBVSEL=0, MICBIAS=0.9*AVDD and when MBVSEL=1,
LABEL
LABEL
0
DEFAULT
0
DEFAULT
0
DEFAULT
000
000
DEFAULT
Microphone Bias Voltage Control
0 = 0.9 * AVDD
1 = 0.65 * AVDD
Microphone Bias Enable
0 = OFF (high impedance output)
1 = ON
Note that the maximum source current
Input BOOST enable
0 = Boost stage OFF
1 = Boost stage ON
Controls the auxiliary amplifier to
the input boost stage:
000=Path disabled (disconnected)
001=-12dB gain through boost
stage
010=-9dB gain through boost
stage
…
111=+6dB gain through boost
stage
boost stage:
000=Path disabled (disconnected)
001=-12dB gain through boost
stage
010=-9dB gain through boost
stage
…
111=+6dB gain through boost
stage
Controls the L2 pin to the input
DESCRIPTION
DESCRIPTION
DESCRIPTION
DESCRIPTION
PD Rev 4.4 July 2009
WM8976
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