WM8956CGEFLSLASHV datasheet(23/80 Pages) WOLFSON

Part #	WM8956CGEFL/V

Description	Hi-Fi DAC with 1W Stereo Class D Speaker Drivers and Headphone Drivers

PDF	80 Pages

Scroll/Zoom	100%

Manufacturer	WOLFSON [Wolfson Microelectronics plc]

Direct Link	http://www.wolfsonmicro.com

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23 / 80 page

Production Data

WM8956

PD, November 2011, Rev 4.1

MICROPHONE BIASING CIRCUIT

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

MBSEL

When

MBSEL=0,

MICBIAS=0.9*AVDD

and

when MBSEL=1,

MICBIAS=0.65*AVDD. The output can be enabled or disabled using the MICB control bit.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

R25 (19h)

Power

management (1)

MICB

Microphone Bias Enable

0 = OFF (high impedance output)

1 = ON

R48 (30h)

Additional Control

(4)

MBSEL

Microphone Bias Voltage Control

0 = 0.9 * AVDD

1 = 0.65 * AVDD

Table 7 Microphone Bias Control

The internal MICBIAS circuitry is shown in Figure 10. The maximum source current capability for

MICBIAS is 3mA. The external biasing resistors therefore must be large enough to limit the MICBIAS

current to 3mA.

Figure 10 Microphone Bias Schematic

WM8956CGEFL/V Datasheet(PDF) 23 Page - Wolfson Microelectronics plc