IR3529
Page 19 of 22 February 12, 2010
PCB Metal and Component Placement
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Lead land width should be equal to nominal part lead width. The minimum lead to lead spacing should be ≥
0.2mm to minimize shorting.
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Lead land length should be equal to maximum part lead length + 0.3 mm outboard extension + 0.05mm
inboard extension. The outboard extension ensures a large and inspectable toe fillet, and the inboard
extension will accommodate any part misalignment and ensure a fillet.
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Center pad land length and width should be equal to maximum part pad length and width. However, the
minimum metal to metal spacing should be ≥ 0.17mm for 2 oz. Copper (≥ 0.1mm for 1 oz. Copper and ≥
0.23mm for 3 oz. Copper).
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Four 0.3mm diameter vias shall be placed in the pad land spaced at 1.2mm, and connected to ground to
minimize the noise effect on the IC and to transfer heat to the PCB.
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No PCB traces should be routed nor vias placed under any of the 4 corners of the IC package. Doing so
can cause the IC to rise up from the PCB resulting in poor solder joints to the IC leads.