Texas Instruments PCM2704, Manual

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DAC
Digital Audio Interface—S/PDIF Output
Channel Status Information
Copyright Management
Digital Audio Interface—I
2
S Interface Output (PCM2706/7)
LRCK
SYSCK
(256 f )
S
BCK
(64 f )
S
R-Channel L-Channel
DOUT
1 1 1
1 1 1
2 2 2
2 2 2
3 3
3 3
MSB MSB MSB LSB LSB
1/f
S
14 14
14 14
15 15
15 15
16 16
16 16
DIN
T0009-04
PCM2704
,,
PCM2705
PCM2706, PCM2707
www.ti.com ....................................................................................................................................................... SLES081F – JUNE 2003 – REVISED JANUARY 2009
The PCM2704/5/6/7 has a DAC that uses an oversampling technique with 128-f
S
second-order multibit noise
shaping. This technique provides extremely low quantization noise in the audio band, and the built-in analog
low-pass filter removes the high-frequency components of the noise-shaping signal. DAC outputs through the
headphone amplifier V
OUT
L and V
OUT
R can provide 12 mW at 32
Ω
, as well as 1.8 V
PP
into a 10-k
Ω
load.
The PCM2704/5/6/7 employs S/PDIF output. Isochronous-out data from the host are encoded to S/PDIF output
DOUT, as well as to DAC analog outputs V
OUT
L and V
OUT
R. Interface format and timing follow the IEC-60958
standard. Monaural data are converted to the stereo format at the same data rate. S/PDIF output is not
supported in the I
2
S I/F enable mode. The implementation of this feature is optional. Note that it is your
responsibility to determin whether to implement this feature in your product or not.
The channel status information is fixed as consumer application, PCM mode, copyright, and digital/digital
converter. All other bits are fixed as 0s, except for the sample frequency, which is set automatically according to
the data received through the USB.
Digital audio data output always is encoded as original with SCMS control. Only one generation of digital
duplication is allowed.
The PCM2706 and PCM2707 can support the I
2
S interface, which is enabled by FSEL (pin 9). In the I
2
S interface
enabled mode, pins 4, 18, 19, 5, and 17 are assigned as DIN, SYSCK, BCK, LRCK, and DOUT, respectively.
They provide digital output/input data in the 16-bit I
2
S format, which also is accepted by the internal DAC. I
2
S
interface format and timing are shown in Figure 22 , Figure 23 , and Figure 24 .
Figure 22. Audio Data Interface Format
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