[AK4425A]

OPERATION OVERVIEW

The external clocks required to operate the AK4425A are MCLK, LRCK and BICK. The master clock (MCLK) should be

synchronized with LRCK but the phase is not critical. The MCLK is used to operate the digital interpolation filter and the

delta-sigma modulator. The MCLK is used to operate the digital interpolation filter and the delta-sigma modulator. There

are two methods to set MCLK frequency. In Manual Setting Mode (ACKS = “0”: Register 00H), the sampling speed is set

by DFS0/1 (Table 1). The frequency of MCLK at each sampling speed is set automatically. (Table 2) When the power

applied, the AK4425A is in Auto Setting Mode. In Auto Setting Mode (ACKS = “1”: Default), as MCLK frequency is

detected automatically (Table 3), and the internal master clock becomes the appropriate frequency (Table 4), it is not

necessary to set DFS0/1.

The AK4425A is automatically placed in power saving mode when MCLK, LRCK and BICK stop during normal

operation mode, and the analog output is forced to 0V(typ). When MCLK, LRCK and BICK are input again, the

AK4425A is powered up. After power-up, the AK4425A is in the power-down mode until MCLK, LRCK and BICK are

input.

DFS1

DFS0

Sampling Rate (fs)

0

0

Normal Speed Mode

8kHz~48kHz

(default)

0

1

Double Speed Mode

60kHz~96kHz

1

0

Quad Speed Mode

120kHz~192kHz

Table 1. Sampling Speed (Manual Setting Mode)

LRCK

(kHz)

MCLK (MHz)

BICK

(MHz)

DFS1

DFS0

Sampling

Speed

fs

128fs

192fs

256fs

384fs

512fs

768fs

1152fs

64fs

0

0

32.0

-

-

8.1920

12.2880

16.3840

24.5760

36.8640

2.0480

0

0

44.1

-

-

11.2896

16.9344

22.5792

33.8688

-

2.8224

0

0

Normal

48.0

-

-

12.2880

18.4320

24.5760

36.8640

-

3.0720

0

1

88.2

11.2896

16.9344

22.5792

33.8688

-

-

-

5.6448

0

1

Double

96.0

12.2880

18.4320

24.5760

36.8640

-

-

-

6.1440

1

0

176.4

22.5792

33.8688

-

-

-

-

-

11.2896

1

0

Quad

192.0

24.5760

36.8640

-

-

-

-

-

12.2880

Table 2. System Clock Example

MCLK

Sampling Speed

1152fs

Normal (fs=32kHz only)

512fs

768fs

Normal

256fs

384fs

Double

128fs

192fs

Quad

Table 3. Sampling Speed(Auto Setting Mode: Default)

MS1127-E-01

2011/03

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