ASAHI KASEI
[AK4395]
OPERATION OVERVIEW
n System Clock
The external clocks, which are required to operate the AK4395, 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. 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). CKS0/1/2 set the frequency of MCLK at each sampling
speed (Table 2). In Auto Setting Mode (ACKS = “1”: Default), as MCLK frequency is detected automatically (Table 6),
and the internal master clock becomes the appropriate frequency, it is not necessary to set DFS0/1 and CKS0/1/2. In
parallel mode, CKS2 and DFS1 are fixed to “0”.
All external clocks (MCLK, BICK and LRCK) should always be present whenever the AK4395 is in normal operation
mode (PD = “H”). If these clocks are not provided, the AK4395 may draw excess current because the device utilizes
dynamic refreshed logic internally. If the external clocks are not present, the AK4395 should be in the power-down mode
(PDN = “L”) or in the reset mode (RSTN = “0”). After exiting reset at power-up etc., the AK4395 is in power-down mode
until MCLK and LRCK are input.
DFS1
DFS0
Sampling Rate (fs)
Default
0
0
1
0
1
0
Normal Speed Mode
30kHz~54kHz
60kHz~108kHz
120kHz~216kHz
Double Speed Mode
Quad Speed Mode
Table 1. Sampling Speed (Manual Setting Mode)
Mode
CKS2
CKS1
CKS0
Normal
Double
Quad
Default
0
1
2
3
4
5
6
7
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
256fs
256fs
384fs
384fs
512fs
512fs
768fs
768fs
128fs
256fs
192fs
384fs
256fs
N/A
N/A
N/A
N/A
N/A
128fs
N/A
192fs
N/A
384fs
N/A
Table 2. System Clocks (Manual Setting Mode)
Note: The master clock at quad speed supports only 128fs or 192fs.
LRCK
fs
32.0kHz
MCLK
BICK
64fs
8.1920MHz 12.2880MHz 16.3840MHz 24.5760MHz 2.0480MHz
256fs
384fs
512fs
768fs
44.1kHz 11.2896MHz 16.9344MHz 22.5792MHz 33.8688MHz 2.8224MHz
48.0kHz 12.2880MHz 18.4320MHz 24.5760MHz 36.8640MHz 3.0720MHz
Table 3. System clock example (Normal Speed Mode @Manual Setting Mode)
MS0040-E-00
2000/7
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AKM [ ASAHI KASEI MICROSYSTEMS ]
