Hi guys;
There are a few points that should be taken in to considerations regarding IPC-SM-782 land pattern and design rules.
As a general rule all SMT reflow pattern should be in comply with SM-782 but however for special cases like :
* PLCC land Patterns:Pls Ensure that the toe and heel clearance of a PLCC device have not been reduce below IPC requirement.Any reduction in term of space would cause inspection and repair problems.
* Fine pitch QFP land patterns:As a general rule , ensure there is at least two component lead widths for the toe fillet in front of the component lead and 2 for the heel fillet behind it. (QFP land pads = 2 Comp lead widths + length of comp foot + 2 component lead widths)-IPC rules tends to have inadequate toe and heel clearances on their QFP land pattern.
* QFP pad pattern widths: Pad width should be the width of the lead of the device + 0.002".
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