AK4125_07 Datasheet, PDF (16/26 Pages) Asahi Kasei Microsystems – 192kHz / 24Bit High Performance Asynchronous SRC

[AK4125]
■ Soft Mute Operation
1. Manual mode
Soft mute operation is performed in the digital domain of the SRC output. Soft mute can be controlled by the SMUTE pin.
When the SMUTE pin changes to “H”, the SRC output data is attenuated by −∞ within 1024 OLRCK cycles. When the
SMUTE pin changes to “L”, the mute is cancelled and the output attenuation gradually changes to 0dB during 1024
OLRCK cycles. If the soft mute is cancelled before mute state after starting the operation, the attenuation is discontinued
and returned to 0dB by the same cycles. The soft mute is effective for changing the signal source.
SMUTE
0dB
(1)
A tte n u a tio n
-∞
1024/fso
(2)
SDTO
Figure 9. Soft Mute Function (Manual Mode)
(1) The output data is attenuated by −∞ during 1024 OLRCK cycles (1024/fso).
(2) If the soft mute is cancelled before attenuating to −∞ after starting the operation, the attenuation is discontinued and
returned to 0dB by the same number of clock cycles.
2. Semi-Auto mode
The soft mute is cancelled automatically by the setting of PLL2-0 pins (Table 2), after the AK4125 detects the rising edge
(PDN pin = “L” → “H”) and the mute is continued during 4410/fso=100ms@fso=44.1kHz. After PDN pin = “L” → “H”
and when the SMUTE pin is “H”, the mute is not cancelled.
PDN pin
“L”
SM UTE pin
0dB
Attenuation
-∞
Don’t care
4410/fso
“L”
(1)
SDTO
Figure 10. Soft Mute Function (Semi-Auto Mode)
(1) The output data is returned to 0dB during 1024 OLRCK cycles (1024/fso).
MS0379-E-04
- 16 -
2007/07