Datasheet

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SLES117A – AUGUST 2004 – REVISED NOVEMBER 2006

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FUNCTION DESCRIPTIONS

Audio data format

Audio format is selected using FMT0 (pin 11) and FMT1 (pin 12). The PCM1794A also supports monaural mode and DF

bypass mode using MONO (pin 1) and CHSL (pin 2). The PCM1794A can select the DF rolloff characteristics.

Table 2. Audio Data Format Select

MONO CHSL FMT1 FMT0 FORMAT STEREO/MONO DF ROLLOFF

0 0 0 0 I

S Stereo Sharp

0 0 0 1 Left-justified format Stereo Sharp

0 0 1 0 Standard, 16-bit Stereo Sharp

0 0 1 1 Standard, 24-bit Stereo Sharp

0 1 0 0 I

S Stereo Slow

0 1 0 1 Left-justified format Stereo Slow

0 1 1 0 Standard, 16-bit Stereo Slow

0 1 1 1 Digital filter bypass Mono –

1 0 0 0 I

S Mono, L-channel Sharp

1 0 0 1 Left-justified format Mono, L-channel Sharp

1 0 1 0 Standard, 16-bit Mono, L-channel Sharp

1 0 1 1 Standard, 24-bit Mono, L-channel Sharp

1 1 0 0 I

S Mono, R-channel Sharp

1 1 0 1 Left-justified format Mono, R-channel Sharp

1 1 1 0 Standard, 16-bit Mono, R-channel Sharp

1 1 1 1 Standard, 24-bit Mono, R-channel Sharp

Soft Mute

The PCM1794A 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

of the DAC output.

De-Emphasis

The PCM1794A 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 PCM1794A detects that the audio input data in the L-channel and the R-channel is continuously zero for

1024 LRCKs in the PCM mode or that the audio input data is continuously zero for 1024 WDCKs in the external filter

mode, the PCM1794A sets ZERO (pin 13) to HIGH.