AK4618 Datasheet, PDF (23/60 Pages) Asahi Kasei Microsystems – 192kHz 24-bit 6ch/12ch Audio CODEC with Microphone Interface

[AK4618]
OPERATION OVERVIEW
■ System Clock
The external clocks which are required to operate the AK4618 in slave mode are MCLK, LRCK and BICK. MCLK
should be synchronized with LRCK but the phase is not critical. There are two methods to set MCLK frequency. In
Manual Setting Mode (ACKS bit= “0”: Default), the sampling speed is set by DFS0, DFS1 (Table 1). The frequency of
MCLK at each sampling speed is set automatically. (Table 3, Table 4, Table 5). In Auto Setting Mode (ACKS bit= “1”),
as MCLK frequency is detected automatically (Table 6) and the internal master clock attains the appropriate frequency
(Table 7), so it is not necessary to set DFS.
In master mode, only MCLK is required. Master Clock Input Frequency should be set with the CKS1-0 bits, and the
sampling speed should be set by the DFS1-0 bits. The frequencies and the duties of the clocks (LRCK, BICK) are not
stabile immediately after setting CKS1-0 bits and DFS1-0 bits up.
After exiting reset at power-up in slave mode, the AK4618 is in power-down mode until MCLK and LRCK are input.
If the clock is stopped, click noise occurs when restarting the clock. Mute the digital output externally if the click noise
influences system applications.
Note: ADC is automatically powered-down in Doble Speed Mode and Quad Speed Mode.
DFS1
0
0
1
1
DFS0
Sampling Speed Mode (fs)
0
Normal Speed Mode
8kHz~48kHz
(default)
1
Double Speed Mode
64kHz~96kHz
0
Quad Speed Mode
128kHz~192kHz
1
N/A
-
(N/A: Not available)
Table 1. Sampling Speed (Manual Setting Mode)
CKS1
0
0
1
1
CKS0
0
1
0
1
Normal Speed
Mode
256fs
384fs
512fs
512fs
Double Speed
Mode
256fs
256fs
256fs
256fs
Quad Speed
Mode
128fs
128fs
128fs
128fs
(default)
Table 2. Master Clock Input Frequency Select (Master Mode)
Note: In Normal Speed Mode, TDM mode (TDM1-0 bits =”01) can be used when CKS1 bit = “1”.
LRCK
fs
32.0kHz
44.1kHz
48.0kHz
256fs
8.1920
11.2896
12.2880
MCLK (MHz)
384fs
12.2880
16.9344
18.4320
512fs
16.3840
22.5792
24.5760
BICK (MHz)
64fs
2.0480
2.8224
3.0720
Table 3. System Clock Example (Normal Speed Mode @Manual Setting Mode)
015000617-E-00
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2015/01