WM8741GEDSSLASHV datasheet(40/64 Pages) WOLFSON

40 / 64 page

WM8741

Production Data

PD, Rev 4.2, October 2009

OVERSAMPLING RATE CONTROL

The user has control of the oversampling ratio of the WM8741, and can set to the device to operate

in low, medium or high rate modes.

For optimum operation of the digital filtering and other

processing on the WM8741 in PCM hardware mode, the user must ensure the correct value of OSR

is set at all times. Table 47 shows the correct settings:

NAME

DESCRIPTION

OSR/DSDR

Oversampling Rate Selection

0 = Low rate (32/44.1/48kHz)

Z = Medium rate (88.2/96kHz)

1 = High rate (176.4/192kHz)

Table 47 OSR/DSDR Hardware Control Pin Function

MUTE PIN

A soft mute can be applied to the WM8741 in the digital domain in all PCM. A logic low on the

MUTEB pin will cause the attenuation to ramp to infinite attenuation at a rate of 1022x(4/fs). Setting

MUTEB high will return the signal gain to its previous value. Figure 26 shows the soft mute

characteristic.

In DSD Direct mode the MUTEB pin controls the analogue mute in the DAC. This analogue mute is

a ‘hard’ mute and is applied and released as soon as the MUTEB pin is toggled.

NAME

DESCRIPTION

MUTEB/

SDOUT

Mute control

0 = Mute on (no output)

1 = Mute off (normal operation

Table 48 MUTEB Hardware Control Pin Function

0.02

0.04

0.06

0.08

0.1

0.12

0.14

Time (s)

Figure 26 Hardware Control Mode Soft Mute Characteristic

WM8741GEDS/V Datasheet(PDF) 40 Page - Wolfson Microelectronics plc