AK4137EQ Datasheet, PDF (43/65 Pages) Asahi Kasei Microsystems – 32bit SRC with PCM/DSD conversion

[AK4137]
(1) Soft mute cycle is set by SMT1-0 pins or SMT2-0 bits (Table 6). The output data is attenuated to 
in the soft mute cycle.
(2) If the soft mute is cancelled before attenuating to , the attenuation is discontinued and the
attenuation level returns to 0dB by the same clock cycles.
DSD Output Mode
In 256fs mode, the output gain is changed by 1/(1024×256)fs..
In 128fs mode, the output gain is changed by 1/(1024×128)fs.
In 64fs mode, the output gain is changed by 1/(1024×64)fs.
SMT2 bit setting is ignored while the soft mute period is in the range from 1024 to 8129/fso.
Semi-Auto Mode
The AK4137 enters Semi-auto Soft Mute mode by detecting power down release (PDN pin = “L” →
“H”) while the SMSEMI pin = “H” or reset release (RSTN bit = “0” → “1”) while the PSN pin = “L”.
The soft mute is cancelled automatically in 4410/FSO=100ms @FSO=44.1kHz after detecting a
rising edge of the PDN pin = “L” → “H” (or RSTN bit “0” → “1”). Soft mute will not be cancelled if the
SMUTE pin is “H” after power–down is released (or SMUTE bit is “1” after reset is released). The
setting of the SMSEMI pin must be changed during the PDN pin is “L”, and the setting of SMSEMI bit
must be changed during RSTN bit = “0”.
PDN
“L”
SMUTE Pin
0dB
Attenuation
-
Don’t Care
4410/fso
SDTO
“L”
(1)
Figure 37. Soft Mute Semi-Auto Mode
(1) The output data is attenuated by  during the soft mute cycle.
(2) When the attenuation level is 0dB by a soft mute release after 4410/FSO, the output signal is able to
mute or release mute by the soft mute cycle in Table 6.
Rev. 0.2
- 43 -
2014/06