MIC45205 datasheet(26/40 Pages) MICROCHIP

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MIC45205

DS20005798B-page 26

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2017 - 2022 Microchip Technology Inc.

7.0

SIMPLIFIED PCB DESIGN

RECOMMENDATIONS

7.1

Periphery I/O Pad Layout and

Large Pad for Exposed Heatsink

The board design should begin with copper/metal pads

that sit beneath the periphery leads of a mounted

B1QFN. The board pads should extend outside the

B1QFN package edge a distance of approximately

0.20 mm per side:

Total pad length = 8.00 mm + (0.20 mm per side × 2

sides) = 8.40 mm.

After completion of the periphery pad design, the larger

exposed pads will be designed to create the mounting

surface of the B1QFN exposed heatsink. The primary

transfer of heat out of the B1QFN will be directly

through the bottom surface of the exposed heatsink. To

aid in the transfer of generated heat into the PCB, the

use of an array of plated through-hole vias beneath the

mounted part is recommended. The typical via hole

diameter is 0.30 mm to 0.35 mm, with center-to-center

pitch of 0.80 mm to 1.20 mm.

FIGURE 7-1:

Package Bottom View vs. PCB Recommended Exposed Metal Trace.

Please note that the exposed metal trace is a “mirror

image” of the package bottom view.

MIC45205 Datasheet(PDF) 26 Page - Microchip Technology