WM8778-EV1M
w
Rev 1.1, February 2004
4
EVALUATION BOARD OPERATION
POWER SUPPLIES
Using appropriate power leads with 4mm connectors, power supplies should be connected
as described in Table 1.
REF-DES
SOCKET NAME
SUPPLY
J1
+5V
+5V
J2
DGND
0V
J3
DVDD
+2.7V to +3.6V
J4
AVDD
+2.7V to +5.5V
J5
AGND
0V
J22
+12V
+12V
J23
-12V
-12V
Table 1 Power Supply Connections
The DGND and AGND connections may be connected to a common GND on the supply with
no reduction in performance.
Note:
Refer to WM8778 datasheet for limitations on individual supply voltages.
Important: Exceeding the recommended maximum voltage can damage EVB
components. Under voltage may cause improper operation of some or all of the EVB
components.
BOARD FUNCTIONALITY
There are three options for inputting digital data into the WM8778 evaluation board. There is
a coaxial input (J7) via a standard phono connector or an optical input (U3) via a standard
optical receiver module. A direct digital input is also available via one side of a 2x8 pin
header (H1).
The analogue input signals are applied to the evaluation board via standard phono
connectors J13 (AINL) and J10 (AINR). The evaluation board provides the option to select an
active or passive anti-alias filter for the analogue input; this can be selected using SW3 and
SW4.
There are two options for outputting digital data from the WM8778 evaluation board. There is
a coaxial output (J6) via a standard phono connector. The digital signals may also be
accessed via one side of a 2x8 pin header (H2).
The line analogue outputs of the board are via phono connectors and can be output as active
external filtered or unfiltered outputs. J19 (UNFILT_VOUTL) and J15 (UNFILT_VOUTR)
provide the unfiltered outputs and J21 (FILT_VOUTL) and J20 (FILT_VOUTR) provide the
active filtered outputs.
All WM8778 device pins are accessible for easy measurement via the 1x14 pin headers (H3
and H4) running up each side of the device.
Level-shift IC’s (U5 and U8) are used to shift the fixed +5V digital input from the CS8427 (U4)
down to the same level as DVDD and vice-versa.
Summary of Contents for WM8778-EV1B
Page 1: ...WM8778 EV1B Evaluation Board User Handbook Rev 1 1...
Page 25: ...WM8778 EV1M w Rev 1 1 February 2004 25 SCHEMATIC LAYOUT Figure 13 Functional Diagram...
Page 26: ...WM8778 EV1M w Rev 1 1 February 2004 26 Figure 14 Digital Input...
Page 27: ...WM8778 EV1M w Rev 1 1 February 2004 27 Figure 15 Software Control...
Page 28: ...WM8778 EV1M w Rev 1 1 February 2004 28 Figure 16 Level Shift...
Page 29: ...WM8778 EV1M w Rev 1 1 February 2004 29 Figure 17 Analogue Input and Output Mute...
Page 30: ...WM8778 EV1M w Rev 1 1 February 2004 30 Figure 18 WM8778...
Page 31: ...WM8778 EV1M w Rev 1 1 February 2004 31 Figure 19 Analogue Output...
Page 32: ...WM8778 EV1M w Rev 1 1 February 2004 32 Figure 20 Power...
Page 33: ...WM8778 EV1M w Rev 1 1 February 2004 33 WM8778 EV1B PCB LAYOUT Figure 21 Top Layer Silkscreen...
Page 34: ...WM8778 EV1M w Rev 1 1 February 2004 34 Figure 22 Top Layer...
Page 35: ...WM8778 EV1M w Rev 1 1 February 2004 35 Figure 23 Bottom Layer...
Page 36: ...WM8778 EV1M w Rev 1 1 February 2004 36 Figure 24 Bottom Layer Silkscreen...
