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Best Land Pattern design for 0402 Resitors?

Dan Gosselin

#32076

Best Land Pattern design for 0402 Resitors? | 14 January, 2005

I have heard of people using a round pad or Home plate design to decrease the incidence of tombstoning on 0402's Anyone have any practical experience on this or is everyone just using the IPC 782 recommended land pattern (28mil x 33mil rectangle pad separated with a 20 mil gap)

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Dan Mendoza

#32077

Best Land Pattern design for 0402 Resitors? | 14 January, 2005

I have used the rectangle shapes and round shapes with no noticible difference. The idea is to design the pads to accept the same solder volume per component. Components over two size pads will favor the higher solder volume side during reflow.

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RDR

#32082

Best Land Pattern design for 0402 Resitors? | 14 January, 2005

We use a 25 x 25 mil square pad with a 18-20mil GAP with great success.

Russ

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Dan Gosselin

#32111

Best Land Pattern design for 0402 Resitors? | 17 January, 2005

Thanks for your input. What would you say is the biggest defect condition you see with 0402's? ANy difference with 0402 caps vs. resistors? Dan

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RDR

#32116

Best Land Pattern design for 0402 Resitors? | 17 January, 2005

Haven't noticed any major difference between C's and R's. Our biggest problem is feeders that will advance to the same location and leave the part in the pocket. We see "billboarding" on R's when the feeder isn't working right. If you have a good pad design with a good profile you should have no problems with 0402 assuming your equipment is capable. 0201 seems to be the same but the feeders really need to be good.

Russ

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