Cirrus Logic CDB4351 - Manual (Page 4)

CDB4351
4 DS566DB3
5. GROUNDING AND POWER SUPPLY DECOUPLING
As with any high-performance converter, the CS4351 requires careful attention to power supply
and grounding arrangements to optimize performance. Figure 2 details the connections to the
CS4351 and Figures 8, 9, and 10 show the component placement and top and bottom layout.
The decoupling capacitors are located as close to the CS4351 as possible. Extensive use of
ground plane fill in the evaluation board yields large reductions in radiated noise.
6. CONTROL PORT SOFTWARE
The CDB4351 is shipped with Windows 95/98/ME-based software as well as Windows
NT/2000/XP drivers for interfacing with the CS4351 control port via the DB25 connector, J16.
The software can be used to communicate with the CS4351 in either SPI
®
or I
2
C mode. See the
readme.txt file for more information.
7. ANALOG OUTPUT FILTERING
The analog output on the CDB4351 has been designed according to the CS4351 datasheet. This
output circuit includes an AC coupling cap, the FET mute circuit, and a single-pole R and C. An
additional load resistance of 5.1 k
Ω
can be jumpered in (J15 and J24) to test the CS4351’s load
driving capability. The FET muting circuit may be bypassed by placing a shunt on J13 and J21.
Table 1. System Connections
CONNECTOR INPUT/OUTPUT SIGNAL PRESENT
+5V Input + 5 V power
VD Input + 3.3 V power for the CS4351 digital supply
VL Input + 1.8 V to +3.3 V power for the CS4351 serial interface
VA Input + 3.3 V power for the CS4351 low-voltage analog
VA_H Input +9 V to +12 V positive supply for the CS4351 high-voltage analog
GND Input Ground connection from power supply
SPDIF INPUT - J11 Input Digital audio interface input via coaxial cable
SPDIF INPUT - OPT1 Input Digital audio interface input via optical cable
PCM INPUT - J9 Input Input for master, serial, left/right clocks and serial data
PC Port Input/Output
Parallel connection to PC for SPI / I
2
C control port signals
EXT CTRL I/O Input/Output
I/O for SPI / I
2
C control port signals
AOUTA and AOUTB Output RCA line-level analog outputs