AK4490EQ Datasheet, PDF (27/68 Pages) Asahi Kasei Microsystems – Premium 32-Bit 2ch DAC

[AK4490]
9. Functional Descriptions
■ D/A Conversion Mode
In serial mode, the AK4490 can perform D/A conversion for either PCM data or DSD data. The D/P bit
controls PCM/DSD mode. When DSD mode, DSD data can be input from DCLK, DSDL and DSDR pins.
When PCM mode, PCM data can be input from BICK, LRCK and SDATA pins. When PCM/DSD mode is
changed by D/P bit, the AK4490 should be reset by RSTN bit. It takes about 2/fs to 3/fs to change the mode. In
parallel mode, the AK4490 performs for only PCM data.
DP bit Interface
0
PCM
1
DSD
Table 1. PCM/DSD Mode Control
When DP bit= “0”, an internal digital filter or external digital filter can be selected. When using an external
digital filter (EX DF I/F mode), data is input to each MCLK, BCK, WCK, DINL and DINR pin. EXDF bit
controls the modes. When switching internal and external digital filters, the AK4490 must be reset by RSTN
bit. A Digital filter switching takes 2~3k/fs.
EXDF bit Interface
0
PCM
1
EX DF I/F
Table 2. Digital Filter Control (DP bit = “0”)
■ System Clock
[1] PCM Mode
The external clocks, which are required to operate the AK4490, are MCLK, BICK and LRCK. 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 modes for MCLK frequency setting: Manual Setting Mode
and Auto Setting Mode. In manual setting mode, MCLK frequency is set automatically (Table 4). In auto
setting mode, sampling speed and MCLK frequency are detected automatically (Table 5) and then the initial
master clock is set to the appropriate frequency (Table 6). When the reset is released (PDN pin = “”), the
AK4490 is in auto setting mode.
The AK4490 is automatically placed in reset state when MCLK and LRCK are stopped during a normal
operation (PDN pin =“H”), and the analog output becomes Hi-z state. When MCLK and LRCK are input
again, the AK4490 exits reset state and starts operation. After exiting system reset (PDN pin =“L”→“H”) at
power-up and other situations, the AK4490 is in power-down mode until MCLK and LRCK are supplied.
The MCLK frequency corresponding to each sampling speed should be provided externally (Table 3).
MS1648-E-03
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2014/11