[AK4685]
The transition between set values is soft transition of 1061 levels in Mode 0. It takes 1061/fs (22ms@fs=48kHz) from
00H to FFH(MUTE). If the PDN pin goes to “L”, the IATL7-0, IATR7-0 (OAT1L7-0, OAT1R7-0, OAT2L7-0,
OAT2R7-0) bits are initialized to 30H(18H). The ATT levels go to their default value when RSTN bit = “0”. When RSTN
bit return to “1”, the ATTs fade to their current value.
■ Digital Soft Mute
The ADC and DAC have a soft mute function. The soft mute operation is performed at digital domain. When the
SMAD/SMDA bits go to “1”, the output signal is attenuated by -∞ during ATT_DATA×ATT transition time (Table 15,
Table 16) from the current ATT level. When the SMAD/SMDA bits are returned to “0”, the mute is cancelled and the
output attenuation gradually changes to the ATT level during ATT_DATA×ATT transition time. If the soft mute is
cancelled before attenuating to -∞ after starting the operation, the attenuation is discontinued and returned to ATT level in
the same cycle. The soft mute is effective for changing the signal source without stopping the signal transmission.
SMAD/SMDA bits
(1)
(1)
ATT Level
Attenuation
(3)
-
∞
GD
GD
(2)
AOUT
Notes:
(1) ATT_DATA×ATT transition time (Table 15, Table 16). For example, in Normal Speed Mode, this time is 1061/fs
cycles (256/fs) at ATT_DATA=00H. ATT transition of the soft-mute is from 00H to FFH
(2) The analog output corresponding to the digital input has group delay, GD.
(3) If the soft mute is cancelled before attenuating to -∞ after starting the operation, the attenuation is discontinued and
returned to ATT level in the same cycle.
Figure 9. Soft Mute Function
MS1106-E-00
2009/08
- 25 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
