Datasheet

MCP1601
DS21762B-page 16  2003-2013 Microchip Technology Inc.
FIGURE 5-3: Top Layer.
The top layer of the board layout is shown in
Figure 5-3. The power conversion process is made up
of two types of circuits. One circuit carries changing
large signals (current, voltage), like C
IN
, C
OUT
, L and
the V
IN
, L
X
P
GND
pins of the MCP1601. The other cir-
cuitry is much smaller in signal and is used to sense,
regulate and control the high-power circuitry. These
components are R
1
, R
2
, C
1
and pins FB, A
GND
. The top
layer is partitioned so that the larger signal connections
are short and wide, while the smaller signals are routed
away from the large signals.
The MCP1601 utilizes two ground pins to separate the
large signal ground current from the small signal circuit
ground. The large signal (“Power Ground”) is labeled
“P
GND
”. The small signal is labeled “Analog Ground” or
“A
GND
”. In Figure 5-3, the P
GND
and the A
GND
are kept
separate on the top layer.
FIGURE 5-4: Bottom Layer.
In Figure 5-4, the bottom layer is a partitioned ground
plane that connects A
GND
to P
GND
near the input
capacitor. The large signal current will circulate on the
top P
GND
partition. The lower partition is used for a
“quiet” ground, where A
GND
is connected.
MCP1601
P
GND
A
GND
P
GND
A
GND
BOT