WM8739 / WM8739L

Advanced Information

AI Rev 2.2 September 2001

29

REGISTER

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

0001001

Active Control

0

ACTIVE

0

Activate Interface

1 = Active

0 = Inactive

0001111

Reset Register

8:0

RESET

not reset

Reset Register

Write 000000000 to register triggers

reset

Table 20 Register Map Description

Note

1.

All other bits not explicitly defined in the register table should be set to zero, unless specified

otherwise (see Powerdown section).

DIGITAL FILTER CHARACTERISTICS

The ADC employs different digital filters. There are 4 types of digital filter, called Type 0, 1, 2 and 3.

The performance of Types 0 and 1 is listed in the table below, the responses of all filters is shown in

the proceeding pages.

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

ADC Filter Type 0 (USB Mode, 250fs operation)

+/- 0.05dB

0

0.416fs

Passband

-6dB

0.5fs

Passband Ripple

+/- 0.05

dB

Stopband

0.584fs

Stopband Attenuation

f > 0.584fs

-60

dB

ADC Filter Type 1 (USB mode, 272fs or Normal mode operation)

+/- 0.05dB

0

0.4535fs

Passband

-6dB

0.5fs

Passband Ripple

+/- 0.05

dB

Stopband

0.5465fs

Stopband Attenuation

f > 0.5465fs

-60

dB

High Pass Filter Corner

Frequency

-3dB

-0.5dB

-0.1dB

3.7

10.4

21.6

Hz

Table 21 Digital Filter Characteristics

TERMINOLOGY

1. Stop Band Attenuation (dB) - the degree to which the frequency spectrum is attenuated (outside audio band)

2. Pass-band Ripple – any variation of the frequency response in the pass-band region