AK4122A Datasheet, PDF (24/54 Pages) Asahi Kasei Microsystems – 24-Bit 96kHz SRC with DIR

[AK4122A]
■ System Reset
Bringing the PDN pin = “L” sets the AK4122A in power-down mode and initializes digital filters. When the PDN pin =
“L”, the SDTO output is “L”. The AK4122A should be reset once by bringing the PDN pin = “L” upon power-up. The
SDTO becomes valid in less than 100ms from the rising edge of PDN after a reset release by clock supply. Until the
SDTO becomes valid, it outputs “L”. After the rising of PDN pin, the SDTIO pin is an input pin.
External clocks
(input / output port) ^{don’t care}
(stable)
don’t care
PDN
(internal state)
Power-down
< 100msec
PLL locktime & fs detection
normal operation
Power-down
SDTO
“0” data
Figure 13. System Reset
normal data
“0” data
■ Sequence of Changing Clocks
A clock change sequence is shown in Figure 14. An internal reset is executed when the input or the output clocks are
changed. The SDTO data is placed “0” during the reset. Within 100ms, the SDTO outputs normal data after the reset.
When the frequency transition occurs gradually without phase change or when the output clock is changed while fso/fsi >
4, the output data may have large distortion for several seconds. A reset should be made by bringing the PDN pin = “L” or
PWN bit = “0” to obtain normal data within 100ms when clocks are changed.
External clocks
(Input port
or Output port)
Clocks 1
Don’t care
Clocks 2
PDN pin
< 100ms
(Internal state)
Normal operation Power-down
PLL lock &
fs detection
Normal operation
SDTIO/SDTO Normal data
Note1 6
Note 17
Normal data
SMUTE
(recommended)
0dB
Att.Level
-∞dB
102 4/fs o
1024 /fs o
Figure 14. Sequence of Changing Clocks
Note 16. The data on SDTO may cause a clicking noise. To prevent this, set SDTI or SDTIO to “0” from GD before the
PDN pin changes to “L”, which will cause the data on SDTO to remain “0”. SMUTE can also remove this
clicking noise.
Note 17. The data on SDTO may cause a clicking noise. To prevent this, set SDTI to “0” for 1024/fso+100ms or more
from the timing when the PDN pin changes to “H” while the SMUTE pin = “H”.
Note 18. The data on SDTO may cause a clicking noise. To prevent this, set SDTI to “0” for 1024/fso+100ms or more
from the timing when the PDN pin changes to “H” while the SMUTE pin = “H”.
MS1076-E-01
- 24 -
2010/05