Datasheet

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SBAS327A − JUNE 2004 − REVISED SEPTEMBER 2004
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14
PRODUCT OVERVIEW
The PCM4204 is a high-performance, four-channel audio
analog-to-digital (A/D) converter designed for use in
professional and broadcast audio applications. The
PCM4204 features 24-bit linear PCM data outputs, as well
as 1-bit Direct Stream Digital (DSD) data output and input
capability for all four channels. Sampling rates up to
216kHz are supported for PCM output formats, while 64x
or 128x oversampled 1-bit data is supported for DSD
modes. Native support for both PCM and DSD data
formats makes the PCM4204 ideal for use in a wide variety
of audio recording and processing applications.
The PCM4204 features 1-bit delta sigma modulators
employing density modulated dither for improved dynamic
performance. Differential voltage inputs are utilized for the
modulators, providing excellent common-mode rejection.
On-chip voltage references are provided for the
modulators, in addition to generating DC common-mode
bias voltage outputs for use with external input circuitry.
Linear phase digital decimation filtering is provided for the
24-bit PCM output, with a minimum stop band attenuation
of −100dB for all sampling modes.
The PCM output mode features clipping flag outputs for
each of the four channels, as well as a digital high-pass
filter for DC removal. The PCM4204 may be configured
using dedicated input pins for sampling mode and audio
data format selection, high-pass filter enable/disable, and
reset/power-down operation.
A +5V power supply is required for the analog section of
the device, while a +3.3V power supply is required for the
digital circuitry. Figure 1 shows the functional block
diagram for the PCM4204.
Audio
Serial
Port
Control
and
Status
V
IN
1+
V
IN
1
−
V
REF
12+
AGND4
V
IN
2+
V
IN
2
−
V
REF
12
−
Power and Ground
System Clock
and
Timing
V
COM
12
Delta−Sigma
Modulator
Delta−Sigma
Modulator
Reference
LRCK
BCK
SDOUT1
SDOUT2
DSD
Data
Port
DSD1
DSD2
DSD3
DSD4
DSDCLK
Digital
DecimationandHighPass
Filters
To Other
Blocks
To /From
Other Blocks
FS0
FS1
FS2
S/M
FMT0
FMT1
FMT2
HPFD
SUB
RST
CLIP1
CLIP2
CLIP3
CLIP4
V
CC
1
AGND1
V
CC
2
AGND2 BGND1 BGND2 BGND3 BGND4
V
DD
1
DGND1
V
DD
2
DGND2
V
DD
3
DGND3
SCKI
V
IN
3+
V
IN
3
−
V
REF
34+
AGND3
V
IN
4+
V
IN
4
−
V
REF
34
−
V
COM
34
Delta−Sigma
Modulator
Delta−Sigma
Modulator
Reference
Figure 1. PCM4204 Functional Block Diagram