Cirrus Logic CDB4365 - Manual (Page 5)

DS670DB3 5
CDB4365
source, remove the shunts on J15 and place a ribbon cable so the signal lines are on the center row and the grounds
are on the right side. R116 and R119 should be populated with 2-k
Ω resistors when using an external I²C source
that does not already provide pull-ups.
5. POWER SUPPLY CIRCUITRY
Power is supplied to the evaluation board by four binding posts: GND, +5V, +12V, and -12V (See Figure 52 ). The
‘+5V’ terminal supplies VA and the rest of the +5-V circuitry on the board. The +3.3-V circuitry is powered from a
regulator. The +2.5 volts required for VD is also provided from an on-board regulator. The +5-V supply should be
set within the recommended values for VA stated in the CS4365 datasheet.
WARNING: Refer to the CS4365 datasheet for maximum allowable voltage levels. Operation outside this range can
cause permanent damage to the device.
6. GROUNDING AND POWER SUPPLY DECOUPLING
As with any high-performance converter, the CS4365 requires careful attention to power supply and grounding ar-
rangements to optimize performance.
Figure 44 details the connections to the CS4365 and Figures 53 , 54 , and 55
show the component placement and top and bottom layout. The decoupling capacitors are located as close to the
CS4365 as possible. Extensive use of ground plane fill in the evaluation board yields large reductions in radiated
noise.
7. ANALOG OUTPUT FILTERING
The analog output on the CDB4365 has been designed according to the CS4365 datasheet. This output circuit in-
cludes an active 2-pole, 50-kHz filter which uses the multiple-feedback topology.
Table 1. System Connections
CONNECTOR INPUT/OUTPUT SIGNAL PRESENT
+5V Input + 5 V power
GND Input Ground connection from power supply
+12V Input +12 V positive supply for the on-board filtering
-12V Input -12 V negative supply for the on-board filtering
S/PDIF IN - J9 Input Digital audio interface input via coax
S/PDIF IN - OPT1 Input Digital audio interface input via optical
PCM INPUT - J11 Input Input for master, serial, left/right clocks and serial data
DSD INPUT - J7 Input Input for DSD serial clock and DSD data
OUTA1-B3 Output RCA line level analog outputs