[AK4492]
■ Synchronize Function (PCM Mode, EXDF Mode)
The AK4492 has a function that resets the internal counter to keep the timing of falling edge of the internal
clock CLK1 and the external clock edge in a certain range. With this synchronize function, group delays
between each device can be kept within 4/256fs when using multiple AK4492’s.
Clock synchronize function becomes valid when input data of both L and R channels are “0” for 8192
times continuously in PCM mode or EXDF mode, when both L and R channels become “0” and kept for
8192 times continuously by attenuation or when RSTN bit = “0”. In PCM mode, the internal counter is
synchronized with a rising edged of LRCK (falling edge of LRCK in I2C mode), and it is synchronized with
a rising edge of WCK in EXDF mode. In this case, the analog output has the same voltage as VCML/R.
This function is disabled by setting SYNCE bit = “0” in register control mode. Figure 60 shows a
synchronizing sequence when the input data is “0” for 8192 times continuously. Figure 61 shows a
synchronizing sequence by RSTN bit.
D/A In
(Digital)
SMUTE
(1)
(1)
ATT_Level
Attenuation
-
GD
GD
GD
(4)
AOUT
(2)
8192/fs
(2)
8192/fs
Both DZFL/R pin
SYNC
SYNC
Operation (2)
Operation (2)
Internal Counter
Reset
(5)
Internal
Data
2~3/fs (3)
Figure 60. Synchronizing Sequenc by Continuous “0” Data Input for 8192 Times
Notes:
(1) Regarding ATT Transition time, refer to “■ Output Volume (PCM Mode, DSD Mode, EXDF Mode)”.
(2) When both L and R channels data are “0” for 8192 times continuously, the DZFL and DZFR pins
become “H” and the synchronize function is valid.
(3) Internal data is fixed to “0” forcibly for 2 to 3/fs when internal counter is reset.
(4) A click noise may occur when the internal counter is reset. This noise is output even if a “0” data is
input. Mute the analog output externally if this click noise affects the system performance.
(5) When the internal clock and external clock are in synchronization, the internal counter is not reset
even if the synchronize function is valid.
016011073-E-00
2016/12
- 77 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
