WM8737CLGEFLSLASHR datasheet(17/40 Pages) WOLFSON

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Production Data

WM8737L

PD, Rev 4.4, January 2012

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

R5 (05h)

ADC Control

8:7

MONOMIX[1:0]

00: Stereo

01: Analogue Mono-mix

10: Digital Mono-mix

11: Reserved

R5 (05h)

ADC Control

MONOUT

Analogue mono-mix format control

0: Left ADC data appears on Left

Channel output and Right ADC data

appears on Right Channel Output.

1: Left ADC data appears on both Left

and Right channel outputs.

Table 5 Mono Mixing Control

Note:

In stereo mode (R5) 00, Bit 1 must always be set to 0.

MICROPHONE BIAS

The MICBIAS output provides a low noise reference voltage suitable for biasing electret type

microphones and the associated external resistor biasing network. The output voltage is derived from

VREF and is programmable in three steps from 0.75

 AVDD to 1.2  AVDD, as shown below. Supply

voltage MVDD must be at least 170mV higher than the desired MICBIAS voltage to ensure correct

MICBIAS operation.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

R6 (06h)

Power

Management

1:0

MICBIAS[1:0]

Microphone Bias Control

00: MICBIAS OFF (powered down,

high-impedance output)

01: VMICBIAS = 0.75  AVDD

10: VMICBIAS = 0.9  AVDD

11: VMICBIAS = 1.2  AVDD

Table 6 MICBIAS Control

The internal MICBIAS circuitry is shown below. MVDD is a separate power supply pin used only for

MICBIAS and the microphone preamplifiers. When MICBIAS < AVDD, then MVDD can be tied to

AVDD. However, when MICBIAS = 1.2

 AVDD, then MVDD must be large enough to generate this

output voltage, i.e. it must be higher than AVDD.

Note:

The maximum voltage for MVDD of 3.6V must be observed.

AGND

MICBIAS

VREF

internal

resistor

MVDD

Figure 6 Microphone Bias Schematic

Note that 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. Please refer to the “Applications

Information” section for recommended external components.

WM8737CLGEFL/R Datasheet(PDF) 17 Page - Wolfson Microelectronics plc

WM8737CLGEFL/R Datasheet(HTML) 17 Page - Wolfson Microelectronics plc

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