WM8986GECOSLASHV datasheet(63/87 Pages) WOLFSON

63 / 87 page

Pre-Production

WM8986

PP, Rev 3.1, February 2007

POWER MANAGEMENT

SAVING POWER BY REDUCING OVERSAMPLING RATE

The default mode of operation of the DAC digital filters is in 64x oversampling mode. Under the

control of DACOSR128 the oversampling rate may be doubled. 64x oversampling results in a slight

decrease in noise performance compared to 128x but lowers the power consumption of the device.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

R10 (0Ah)

DAC control

DACOSR128

DAC oversample rate select

0 = 64x (lowest power)

1 = 128x (best SNR)

Table 37 DAC Oversampling Rate Selection

LOW POWER MODE

If only limited functionality is required, the WM8986 can be put into a low power mode. In this mode,

the DSP core runs at half of the normal rate, reducing digital power consumption of the core by half.

For DAC low power only, 3D enhancement with 2-Band equaliser functionality is permitted, where

only Band 1 (low shelf) and Band 5 (high shelf) can be used. .

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

R7 (07h)

Additional Ctrl

M128ENB

0 = low power mode enabled

1 = low power mode disabled

Table 38 DSP Core Low Power Mode Control

The register settings for this low-power mode are detailed below. The device will not enter low power

unless in this register configuration, regardless of M128ENB.

For pop-free operation of the device it is recommended to change the M128ENB low power

functionality only when both DACs are disabled, i.e. when DACENL=0 and DACENR=0.

FUNCTION

SETTING

DESCRIPTION

DAC low power

M128ENB

DACENL

DACENR

Either or both of DACENL and

DACENR must be set (mono or

stereo mode)

Table 39 DSP Core Low Power Mode Register Settings

VMID

The analogue circuitry will not operate unless VMID is enabled. 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.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

R1 (01h)

Power

management 1

1:0

VMIDSEL

Reference string impedance to VMID pin

00= off (250kΩ VMID to AGND1)

01=75kΩ

10=300kΩ

11=5kΩ

Table 40 VMID Impedance Control

BIASEN

The analogue amplifiers will not operate unless BIASEN is enabled.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

R1 (01h)

Power

management 1

BIASEN

Analogue amplifier bias control

0 = disabled

1 = enabled

Table 41 Analogue Bias Control

WM8986GECO/V Datasheet(PDF) 63 Page - Wolfson Microelectronics plc

WM8986GECO/V Datasheet(HTML) 63 Page - Wolfson Microelectronics plc

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