SM5878AM Datasheet, PDF (14/16 Pages) Nippon Precision Circuits Inc – 3rd-order , 2-channel D/A converter

SM5878AM/AV
Soft Mute (SMUTE)
Soft mute mode is selected when MODE is HIGH.
The up/down counter is switched to internal clock
drive, and soft mute operation is controlled by
MUTE only.
When MUTE goes HIGH, the up/down counter
counts down. The total time to go from 0 to
maximum mute is 1024/fs. This corresponds to
approximately 23.2 ms at fs = 44.1 kHz.
When MUTE is LOW, soft mute is released. The
attenuation counter output counts up, increasing the
gain. The time taken to return to 0 dB is also 1024/fs.
Soft mute operation is shown in figure 2.
Upon system initialization or when MODE changes
state, mute is released, which corresponds to the
maximum gain of 0 dB.
MUTE
0 dB
Gain
–
1024/fs
1024/fs
Figure 2. Soft mute operation example
Infinity-Zero (MUTEO)
The SM5878AM/AV outputs an infinity-zero
detection output signal under the following
circumstances.
s From immediately after a reset input on RSTN
until the initialization cycle finishes and the first
data cycle occurs.
s When an infinity-zero occurs in the input data.
When an infinity-zero is detected, a period of 2¹⁴
× (1/fs) ≈ 0.37 seconds takes place before
MUTEO goes HIGH.
LRCI
1
2
3
8
9
2¹⁴/fs
DI
Signal
No Signal
Signal
RSTN
MUTEO
Initialize
Figure 3. MUTEO output timing
TIMING DIAGRAMS
Input Timing (DI, BCKI, LRCI)
1/fs
MSB
LSB
MSB
LSB
16 bits
16 bits
Left channel
Right channel
DI
BCKI
(64fs max)
LRCI
NIPPON PRECISION CIRCUITS—14