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SLES080B – MAY 2003 – REVISED NOVEMBER 2003
FUNCTION DESCRIPTIONS
Audio data format
Audio format is selected using FMT0 (pin 11) and FMT1 (pin 12). The PCM1794 also supports monaural mode and DF
bypass mode using MONO (pin 1) and CHSL (pin 2). The PCM1794 can select the DF rolloff characteristics.
Table 2. Audio Data Format Select
MONO
CHSL
FMT1
FMT0
FORMAT
STEREO/MONO
Stereo
DF ROLLOFF
Sharp
Sharp
Sharp
Sharp
Slow
2
I S
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Left-justified format
Standard, 16-bit
Standard, 24-bit
Stereo
Stereo
Stereo
2
I S
Stereo
Left-justified format
Standard, 16-bit
Stereo
Slow
Stereo
Slow
Digital filter bypass
Mono
–
2
I S
Mono, L-channel
Mono, L-channel
Mono, L-channel
Mono, L-channel
Mono, R-channel
Mono, R-channel
Mono, R-channel
Mono, R-channel
Sharp
Sharp
Sharp
Sharp
Sharp
Sharp
Sharp
Sharp
Left-justified format
Standard, 16-bit
Standard, 24-bit
2
I S
Left-justified format
Standard, 16-bit
Standard, 24-bit
Soft Mute
The PCM1794 supports mute operation. When MUTE (pin 10) is set to HIGH, both analog outputs are transitioned
to the bipolar zero level in –0.5-dB steps with a transition speed of 1/f per step. This system provides pop-free muting
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of the DAC output.
De-Emphasis
The PCM1794 has a de-emphasis filters for the sampling frequency of 44.1 kHz. The de-emphasis filter is controlled
using DEM (pin 3).
Zero Detect
When the PCM1794 detects that the audio input data in the L-channel and the R-channel is continuously zero for
1024 f , the PCM1794 sets ZERO (pin 13)to HIGH.
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