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AK4387 Datasheet, PDF (12/21 Pages) Asahi Kasei Microsystems – 106dB 192kHz 24-Bit 2ch ΔΣ DAC | |||
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ASAHI KASEI
[AK4387]
 Zero Detection
The AK4387 has channel-independent zeros detect function. When the input data at each channel is continuously zeros
for 8192 LRCK cycles, DZF pin of each channel goes to âHâ. DZF pin of each channel immediately goes to âLâ if input
data of each channel is not zero after going DZF âHâ. If RSTN bit is â0â, DZF pins of both channels go to âHâ. DZF pin
of both channels go to âLâ at 2~3/fs after RSTN bit returns to â1â. Zero detect function can be disabled by DZFE bit. In
this case, DZF pins of both channels are always âLâ. DZFB bit can invert the polarity of DZF pin.
 Soft Mute Operation
Soft mute operation is performed at digital domain. When the SMUTE bit goes to â1â, the output signal is attenuated by
-â during ATT_DATAÃATT transition time (Table 9) from the current ATT level. When the SMUTE bit is returned to
â0â, the mute is cancelled and the output attenuation gradually changes to the ATT level during ATT_DATAÃATT
transition time. If the soft mute is cancelled before attenuating to -â after starting the operation, the attenuation is
discontinued and returned to ATT level by the same cycle. The soft mute is effective for changing the signal source
without stopping the signal transmission.
SMUTE bit
ATT Level
(1)
Attenuation
(1)
(3)
-â
GD
GD
(2)
AOUT
DZF pin
(4)
8192/fs
Notes:
(1) ATT_DATAÃATT transition time (Table 9). For example, in Normal Speed Mode, this time is 1020LRCK cycles
(1020/fs) at ATT_DATA=255.
(2) The analog output corresponding to the digital input has a group delay, GD.
(3) If the soft mute is cancelled before attenuating to -â after starting the operation, the attenuation is discontinued and
returned to ATT level by the same cycle.
(4) When the input data at each channel is continuously zeros for 8192 LRCK cycles, DZF pin of each channel goes to
âHâ. DZF pin immediately goes to âLâ if input data are not zero after going DZF âHâ.
Figure 5. Soft Mute and Zero Detection
MS0429-E-00
- 12 -
2005/09
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