PCM1741/E2K BURR-BROWN [Burr-Brown Corporation], PCM1741/E2K Datasheet - Page 15

• Manufacturer Part Number: PCM1741/E2K
• Description: +3.3V Single-Supply, 24-Bit, 96kHz Sampling Enhanced Multilevel, Delta-Sigma, Audio DIGITAL-TO-ANALOG CONVERTER
• Manufacturer: BURR-BROWN [Burr-Brown Corporation]

PCM1741
ANALOG OUTPUTS
The PCM1741 includes two independent output channels:
V
of driving 2.05Vp-p typical into a 5k AC-coupled load. The
internal output amplifiers for V
DC common-mode (or bipolar zero) voltage, equal to V
The output amplifiers include an RC continuous-time filter that
helps to reduce the out-of-band noise energy present at the
DAC outputs, due to the noise shaping characteristics of the
PCM1741’s delta-sigma DACs. The frequency response of this
filter is shown in Figure 8. By itself, this filter is not enough to
attenuate the out-of-band noise to an acceptable level for many
applications, therefore, an external low-pass filter is required to
provide sufficient out-of-band noise rejection. Further discus-
sion of DAC post-filter circuits is provided in the Applications
Information section of this data sheet.
V
One unbuffered common-mode voltage output pin, V
(pin 10), is brought out for decoupling purposes. This pin is
FIGURE 9. Biasing External Circuits Using the V
COM
OUT
SBAS175
L and V
OUTPUT
OUT
(b) Using a Voltage Follower to Buffer V
(a) Using V
R. These are unbalanced outputs, each capable
COM
x = L or R
PCM1741
PCM1741
to Bias a Single-Supply Filter Stage
V
OUT
V
V
OUT
COM
COM
L and V
x
10 F
+
OUT
+
+
R are biased to the
10 F
10 F
R
COM
1
when Biasing Multiple Nodes
COM
CC
OPA342
/2.
R
COM
C
Pin.
2
2
V
CC
R
3
FIGURE 8. Output Filter Frequency Response.
nominally biased to a DC voltage level equal to V
pin may be used to bias external circuits. Figure 9 shows an
example of using the V
tions.
C
1
–10
–20
–30
–40
–50
–60
Buffered
2
3
V
0
0.1
OPA2342
COM
1/2
V
CC
1
1
ANALOG FILTER PERFORMANCE
COM
Frequency (kHz)
(100Hz-10MHz)
A
10
pin for external biasing applica-
V
Filtered
Output
–1, where A
100
V
–
1K
R
R
2
1
CC
/2. This
10K
15