PCM1738E2K BURR-BROWN [Burr-Brown Corporation], PCM1738E2K Datasheet - Page 31

• Manufacturer Part Number: PCM1738E2K
• Description: 24-Bit, 192kHz Sampling, Advanced Segment, Audio-Stereo DIGITAL-TO-ANALOG CONVERTER
• Manufacturer: BURR-BROWN [Burr-Brown Corporation]

PCM1738
BYPASS AND DECOUPLING CAPACITOR
REQUIREMENTS
Various sized decoupling capacitors can be used, with no
special tolerances being required. All capacitors should be
located as close as physically possible to the power supply
and reference pins of the PCM1738 to reduce noise pickup
from surrounding circuitry. Aluminum electrolytic capaci-
tors that are designed for hi-fi audio applications are recom-
mended for larger values, while metal-film or monolithic
ceramic capacitors are recommended for smaller values.
I/V SECTION
I/V conversion, using the circuit shown in Figure 9, achieves
data-sheet performance (see Figure 9). To obtain 0.0005%
THD+N, 117dB signal-to-noise ratio audio performance, THD+N
and input noise performance an op amp IC must be considered.
Input noise of the op amp directly effects the output noise level
of the application.
FIGURE 16. Audio Data Input Format for External Digital Filter (Internal DF Bypass Mode) Application.
FIGURE 17. Audio Interface Timing for External Digital Filter (Internal DF Bypass Mode) Application.
SBAS174B
Audio Data Word = 16 Bit
Audio Data Word = 20 Bit
Audio Data Word = 24 Bit
DATAR
DATAL
WDCK
BCK
DATAR
DATAR
DATAR
DATAL
DATAL
DATAL
WDCK
BCK
15
19
23
SYMBOL
t
t
t
t
t
t
t
BCY
BCL
BCH
BL
LB
DS
DH
16
20
24
t
BCH
WDCK Falling Edge to BCKIN Rising Edge
BCK Rising Edge to WDCK Falling Edge
t
BCY
BCK Pulse Width HIGH
BCK Pulse Cycle Time
BCK Pulse Width LOW
DATA Set-Up Time
1
DATA Hold Time
t
BCL
PARAMETER
MSB
2
t
DS
3
4
1
5
t
t
BL
DH
MSB
2
6
7
3
All components of the I/V section should be located physi-
cally close to the PCM1738 current outputs. All connections
should be made as short as possible to eliminate pickup of
radiated noise.
POST LOW-PASS FILTER DESIGN
The out-of-band noise level and sampling spectrum level are
much lower than typical delta-sigma type DACs, due to the
combination of a high-performance digital filer and the
advanced segment DAC architecture. The use of a second-
or third-order filter is recommended for the post low-pass
filter (see Figure 9 for a second-order filter) following the I/
V conversion stage. The cutoff frequency of the post LPF is
dependent upon the application, given the variety of sam-
pling rates supported by the CD-DA, DVD-M, DVD-A, and
SACD systems.
4
8
1/4f
1
5
9
S
or 1/8f
MSB
10
2
6
MIN
18
t
7
7
5
5
5
5
LB
S
11
3
7
12
4
8
13
5
9
10
14
MAX
6
11
15
7
12
16
8
n
13
17
9
UNITS
10
14
18
ns
ns
ns
ns
ns
ns
s
11
15
19
12
16
20
13
17
21
50% of V
50% of V
50% of V
14
18
22
LSB
LSB
LSB
15 16
19 20
23 24
DD
DD
DD
31