Datasheet

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SBAS291C − AUGUST 2003 − REVISED DECEMBER 2004
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14
LRCK
BCK
DATA0
DATA1
SCKI
RST
MUTE
SUB
CS
CCLK
CDIN
CDOUT
MODE
V
REF
1+
V
OUT
1+
V
OUT
1
−
V
REF
1
−
V
REF
2+
V
OUT
2+
V
OUT
2
−
V
REF
2
−
V
COM
1
V
REF
3+
V
OUT
3+
V
OUT
3
−
V
REF
3
−
V
REF
4+
V
OUT
4+
V
OUT
4
−
V
REF
4
−
V
COM
2
Digital
Filtering
and
Functions
Audio
Serial
Port
Control
and
SPI Port
Digital
Power
Analog
Power
System Clock
and
Timing
V
CC
1
AGND1
V
CC2
1
AGND2
V
DD
DGND
V
DD
D/A Converter
and
Output Filter
D/A Converter
and
Output Filter
D/A Converter
and
Output Filter
D/A Converter
and
Output Filter
Figure 2. PCM4104 Functional Block Diagram for Software Mode
ANALOG OUTPUTS
The PCM4104 provides four differential voltage outputs,
corresponding to audio channels 1 through 4. V
OUT
1+ (pin
1) and V
OUT
1− (pin 2) correspond to Channel 1. V
OUT
2+
(pin 47) and V
OUT
2− (pin 46) correspond to Channel 2.
V
OUT
3+ (pin 38) and V
OUT
3− (pin 39) correspond to
Channel 3. V
OUT
4+ (pin 36) and V
OUT
4− (pin 35)
correspond to Channel 4.
Each differential output is typically capable of providing
6.15V full-scale (differential) into a 600Ω output load. The
output pins are internally biased to the common-mode (or
bipolar zero) voltage, which is nominally V
CC
/2. The output
section of each D/A converter channel includes a
single-pole, switched capacitor low-pass filter circuit. The
switched capacitor filter response tracks with the sampling
frequency of the D/A converter and provides attenuation of
the out-of-band noise produced by the delta-sigma
modulator. An external two-pole continuous time filter is
recommended to further reduce the out-of-band noise
energy and to band limit the output spectrum to
frequencies suitable for audio reproduction. Refer to the
Applications Information section of this data sheet for
recommended output filter circuits.
VOLTAGE REFERENCES
The PCM4104 includes high and low reference pins for
each output channel. V
REF
1+ (pin 5) and V
REF
1− (pin 4)
correspond to Channel 1. V
REF
2+ (pin 44) and V
REF
2− (pin
43) correspond to Channel 2. V
REF
3+ (pin 41) and V
REF
3−
(pin 42) correspond to Channel 3. V
REF
4+ (pin 32) and
V
REF
4− (pin 33) correspond to Channel 4.
The high reference (+) pin may be connected to the
corresponding V
CC
supply or an external +5.0V reference,
while the low reference (−) pin is connected to analog
ground. A 0.01µF bypass capacitor should be placed