MCP1601_13 datasheet(16/24 Pages) MICROCHIP

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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 CIN, COUT, L and

the VIN, LX PGND 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 R1, R2, C1 and pins FB, AGND. 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

“PGND”. The small signal is labeled “Analog Ground” or

“AGND”. In Figure 5-3, the PGND and the AGND 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 AGND to PGND near the input

capacitor. The large signal current will circulate on the

top PGND partition. The lower partition is used for a

“quiet” ground, where AGND is connected.

MCP1601

GND

BOT

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