PCM1738E2K BURR-BROWN [Burr-Brown Corporation], PCM1738E2K Datasheet - Page 24

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

24
APPLICATION FOR EXTERNAL DIGITAL FILTER INTERFACE
FIGURE 10. Connection Diagram for External Digital Filter (Internal DF Bypass Mode) Application.
APPLICATIONS FOR INTERFACING WITH THE
EXTERNAL DIGITAL FILTER PART
For some applications, it may be desirable to use an external
digital filter to perform the interpolation function, as it may
provide improved stopband attenuation or other special fea-
tures not available with the PCM1738’s internal digital filter.
The PCM1738 supports the use of an external digital filter,
including:
• The DF1704 and DF1706 from Texas Instruments.
• Pacific Microsonics PMD100/200 HDCD Filter/Decoder ICs.
• Programmable Digital Signal Processors.
The external digital-filter application mode is available by
programming the following bits in the corresponding control
registers:
WDCK (Word Clock)
DF1704
DF1706
PMD200
DFTH = 1 (Register 20)
DME = 0 (Register 18)
DATA-R
DATA-L
BCK
SCK
Control
Mode
10
11
12
13
14
1
2
3
4
5
6
7
8
9
RST
ZEROL
ZEROR
WDCK
DATAL
BCK
SCKI
DGND
V
SCKO
MDO
MDI
MC
CS
DD
The pins used to provide the serial interface for the external
digital filter are shown in the application diagram of Figure 10.
The Word (WDCK) and Bit (BCK) clock signals, as well as
the audio data inputs (DATAL and DATAR) must be operated
at 8x or 4x the original sampling frequency at the input of the
digital filter.
SYSTEM CLOCK (SCKI) AND INTERFACE TIMING
The PCM1738, in external digital filter application, allows
any system-clock frequency synchronized with BCK and
WDCK. The system clock may be phase free with BCK and
WDCK. See Figure 17 for interface timing among WDCK,
BCK, DATAL, and DATAR.
AUDIO FORMAT
In external Digital-Filter Interface mode, the PCM1738
supports a right-justified audio format interface including
16-, 20-, and 24-bit audio data (see Figure 16) that should be
selected by FMT[2:0] of Control Register 18.
AGND2
AGND1
DATAR
I
I
I
I
V
V
V
OUT
OUT
OUT
OUT
V
V
V
COM
COM
COM
I
CC
CC
CC
REF
R+
R–
L–
L+
3
2
1
3
2
1
28
27
26
25
24
23
22
21
20
19
18
17
16
15
Same as Standard
Output Stage
Application
PCM1738
Analog
SBAS174B