Datasheet

© 2008 Microchip Technology Inc. DS21298E-page 23
MCP3204/3208
FIGURE 6-3: The MCP601 Operational Amplifier is used to implement a second order anti-aliasing
filter for the signal being converted by the MCP3204.
6.4 Layout Considerations
When laying out a printed circuit board for use with
analog components, care should be taken to reduce
noise wherever possible. A bypass capacitor should
always be used with this device, placed as close as
possible to the device pin. A bypass capacitor value of
1 µF is recommended.
Digital and analog traces should be separated as much
as possible on the board, with no traces running
underneath the device or the bypass capacitor. Extra
precautions should be taken to keep traces with high
frequency signals (such as clock lines) as far as
possible from analog traces.
Use of an analog ground plane is recommended in
order to keep the ground potential the same for all
devices on the board. Providing V
DD
connections to
devices in a “star” configuration can also reduce noise
by eliminating return current paths and associated
errors (see Figure 6-4). For more information on layout
tips when using A/D converters, refer to AN688,
“Layout Tips for 12-Bit A/D converter Applications”.
FIGURE 6-4: V
DD
traces arranged in a
‘Star’ configuration in order to reduce errors
caused by current return paths.
MCP3204
V
DD
10 µF
IN-
IN+
-
+
V
IN
C
1
C
2
V
REF
4.096V
Reference
1µF
1µF
0.1 µF
MCP601
R
1
R
2
R
3
R
4
MCP1541
V
DD
Connection
Device 1
Device 2
Device 3
Device 4