WM8758CBGEFLSLASHV datasheet(76/90 Pages) WOLFSON

76 / 90 page

WM8758B

Production Data

PD, Rev 4.4, January 2012

There are 3 modes of low power operation, as detailed below. The device will not enter low power

unless in one of these register configurations, regardless of M128ENB.

FUNCTION

SETTING

DESCRIPTION

ADC low power

M128ENB

ADCENL

ADCENR

DACENL

DACENR

EQ3DMODE

1 (DAC path)

Either or both of ADCENL and

ADCENR must be set (mono or

stereo mode)

DAC low power

M128ENB

ADCENL

ADCENR

DACENL

DACENR

Either or both of DACENL and

DACENR must be set (mono or

stereo mode)

EQ3DMODE = 0: EQ in ADC path

EQ3DMODE = 1: EQ in DAC path

Table 55 DSP Core Low Power Modes for ADC Only and DAC Only Modes

VMID

The analogue equalizer 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 startup time of the

VMID circuit.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

Power

management 1

1:0

VMIDSEL

Reference string impedance to VMID pin

(Determines startup time):

00 = off (250kΩ VMID to AGND1)

01 = 100kΩ

10 = 500kΩ

11 = 10kΩ (for fast startup)

Table 56 VMID Impedance Control

BIASEN

The analogue amplifiers will not operate unless BIASEN is enabled.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

Power

management 1

BIASEN

Analogue amplifier bias control

0 = disabled

1 = enabled

Table 57 Analogue Bias Control

HALFOPBIAS

HALFOPBIAS halves the bias current to the output drivers (OUT1, OUT2, OUT3). Setting

HALFOPBIAS will reduce the quiescent current from AVDD by 0.5mA but will degrade the THD+N

significantly.

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

R61

Bias Control

HALFO

PBIAS

HALFOPBIAS (Do not use)

0 = disabled

1 = enabled (Reduces AVDD current by

0.5mA)

Table 58 HALFOPBIAS Control

Wolfson’s recommendation is: Do not use HALFOPBIAS

WM8758CBGEFL/V Datasheet(PDF) 76 Page - Wolfson Microelectronics plc

WM8758CBGEFL/V Datasheet(HTML) 76 Page - Wolfson Microelectronics plc

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