AD1849K Analog Devices, AD1849K Datasheet - Page 24

• Manufacturer Part Number: AD1849K
• Description: Serial-Port 16-Bit SoundPort Stereo Codec
• Manufacturer: Analog Devices

AD1849K
Analog Devices recommends a split ground plane as shown in
Figure 22. The analog plane and the digital plane are connected
directly under the AD1849K. Splitting the ground plane directly
under the SoundPort Codec is optimal because analog pins will
be located above the analog ground plane and digital pins will
be located directly above the digital ground plane for the best
isolation. The digital ground and analog grounds should be tied
together in the vicinity of the AD1849K. Other schemes may
also yield satisfactory results.
Figure 23 illustrates the “zero-chip” interfaces of the AD1849K
SoundPort Codec to four of Analog Devices’ Fixed-Point
DS Ps. The ADSP-2111, ADSP-2101 and ADSP-2115 use
their multichannel serial port for the data interface and flag
outputs for D/C. The ADSP-2105 has a single serial port which
operates in its frameless mode. Because the ADSP-2105 lacks a
flag output, it alone does require additional circuitry to generate
D/C. Shown is an implementation using a single D-flop, an
OR-gate, and two pull-down resistors.
LINE IN
10 F
SUPPLY
V
DD
+5V
560pF
560pF
5.1k
5.1k
NPO
NPO
UNUSED INPUTS SHOULD BE GROUNDED AND NC'S LEFT UNCONNECTED
INPUT CIRCUIT
MICROPHONE
47k
PREFERRED
0.1 F
1 F
10 F
Figure 21. Typical Connection Diagram
1 F
0.33 F
0.33 F
FERRITE
5.1k
5.1k
0.1 F
1 F
V
LINL
LINR
MINL
MINR
CMOUT
C0
C1
GNDA
GNDA
PDN
PIO0
PIO1
GNDD GNDD GNDD
V
REF
DD
AD1849K
0.1 F
V
DD
LOUT0R
LOUT1R
LOUT1C
LOUT0L
LOUT1L
0.1 F
MOUTR
COUT2
RESET
FSYNC
COUT1
MOUT
0.1 F
SDRX
SCLK
SDTX
V
CIN2
TSIN
CIN1
V
V
DD
CC
CC
0.1 F
FERRITE
1 F
1 F
1 F
LINE OUT 1 OR
HEADPHONE
PREFERRED
24.576MHz
CIRCUIT
16.9344MHz
20–64pF
1.6
1 F
47k
47k
MONO
SPEAKER
0.1 F
OUT 0
LINE
20k
–24–
Low level ADSP-21xx software drivers for the AD1849K are
supplied with the AD1849K Evaluation Board. Source and
object codes arc available from your Analog Devices Sales
Representative or on the Analog Devices DSP Bulletin Board.
The DSP Bulletin Board telephone number is [phone],
8 data bits, no parity, 1 stop bit, 300 to 2400 baud.
Note that the interface to the Texas Instruments TMS320C25
must be significantly more complicated than these three
examples because the C25’s serial port cannot be a master,
which is required of the external controller during Control
Mode.
Figure 23. Interfaces to Analog Devices’ Fixed-Point
DS Ps
Figure 22. AD1849K Recommended Ground Plane
ADSP-2111
ADSP-2101
ADSP-2115
ADSP-2105
RESET
DIGITAL GROUND PLANE
SCLK0
SCLK0
SCLK
RFS0
RFS0
DMS
DR0
DR0
RFS
DT0
DT0
TFS
FL0
WR
FO
DR
DT
D8
AD1849K
PDN
N/C
10k
D
LOUT0R
C0
10k
ANALOG GROUND PLANE
CLR
Q
SCLK
FSYNC
TSIN
SDRX
SDTX
D/C
SCLK
FSYNC
TSIN
SDRX
SDTX
D/C
SCLK
FSYNC
TSIN
SDRX
SDTX
D/C
RESET
AD1849K
AD1849K
AD1849K
REV. 0