[AK4372]
■ EXT Mode (PMPLL bit = “0”: Default)
The AK4372 can be placed in external clock mode (EXT mode) by setting the PMPLL bit to “0”. In EXT mode, the
master clock can directly input to the DAC via the MCKI pin without going through the PLL. In this case, the sampling
frequency and MCKI frequency can be selected by FS3-0 bits (Table 11). In EXT mode, PLL4-0 bits are ignored. MCKO
output is enabled by MCKO bit. The MCKO output frequency can be controlled by PS1-0 bits. If the sampling frequency
is changed during normal operation of the DAC (PMDAC bit = “1”), the input must be muted by SMUTE bit = “1”, or set
to “0” data.
LRCK and BICK are output from the AK4372 in master mode(Figure 15). The clock input to the MCKI pin should
always be present whenever the DAC is in normal operation (PMDAC bit = “1”). If these clocks are not provided, the
AK4372 may draw excessive current and will not operate properly because it utilizes these clocks for internal dynamic
refresh of registers. If the external clocks are not present, the DAC should be placed in power-down mode (PMDAC bit =
“0”).
AK4372
MCKO
DSP or μP
256fs, 384fs, 512fs,
768fs or 1024fs
MCKI
BICK
LRCK
MCLK
BCLK
LRCK
32fs, 64fs
1fs
SDTO
SDATA
Figure 15. EXT Master Mode
The external clocks required to operate the AK4372 in slave mode are MCKI, LRCK and BICK(Figure 16). The master
clock (MCKI) should be synchronized with the sampling clock (LRCK). The phase between these clocks does not matter.
All external clocks (MCKI, BICK and LRCK) should always be present whenever the DAC is in normal operation mode
(PMDAC bit = “1”). If these clocks are not provided, the AK4372 may draw excessive current and will not operate
properly, because it utilizes these clocks for internal dynamic refresh of registers. If the external clocks are not present, the
DAC should be placed in power-down mode (PMDAC bit = “0”).
AK4372
MCKO
DSP or μP
256fs, 384fs, 512fs,
768fs or 1024fs
MCKI
BICK
LRCK
MCLK
BCLK
LRCK
32fs, 64fs
1fs
SDTO
SDATA
Figure 16. EXT Slave Mode
MS0684-E-02
2008/12
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AKM [ ASAHI KASEI MICROSYSTEMS ]
