sm5876 Nippon Precision Circuits Inc, (NPC), sm5876 Datasheet - Page 15

• Manufacturer Part Number: sm5876
• Description: 3rd-order, 2-channel D/a Converter
• Manufacturer: Nippon Precision Circuits Inc, (NPC)

Output mode setting (MDT 4-bit data)
The left-channel and right-channel outputs can be set
to any one of 16 different modes, as shown in table 2.
Table 2. Output mode control
“Stereo” is the default after system reset.
“Mute” refers to soft muting.
Soft mute (output mode setting)
The channel output muting set by the output mode
control 4-bit data is soft mute mode.
The attenuation counter output decrements by 1 step
at a time, reducing the gain. The signal is completely
muted after a time of (1024/fs), which corresponds to
approximately 23.2 ms when fs = 44.1 kHz.
Conversely, when soft mute is released using the out-
put mode control, the attenuation counter output
increments by 1 step at a time, increasing the gain.
The time taken to return to 0 dB from full muting is
also (1024/fs).
When an attenuation value is set, the output gain
decreases from the value set by the attenuation data
until the gain is
output gain increases from the current value until the
gain is 0 dB.
Soft mute operation is shown in figure 3.
PL0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
PL1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
. Similarly for mute release, the
PL2
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
PL3
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
SM5876AM
Left-channel output
(L + R)/2
(L + R)/2
(L + R)/2
(L + R)/2
Mute
Mute
Mute
Mute
Upon system reset initialization, mute is released,
which corresponds to the maximum gain of 0 dB.
Attenuator control (ATC flag)
The attenuator control (ATC) flag is input on MDT.
When the ATC flag is HIGH, the left-channel and
right-channel attenuator data is common. In this
mode, the left-channel data is used for both channels.
Gain
R
R
R
R
L
L
L
L
MUTE
0 dB
–
Figure 3. Soft mute operation example
Right-channel output
(L + R)/2
(L + R)/2
(L + R)/2
(L + R)/2
NIPPON PRECISION CIRCUITS—15
Mute
Mute
Mute
Mute
1024/fs
R
R
R
R
L
L
L
L
1024/fs
Reverse
Stereo
Notes
Mute