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Design guidelines for solder thief pads

Charles Stringer

#11549

Design guidelines for solder thief pads | 7 May, 1999

This is not strictly a surface mount query but any input welcome I am thinking of using surface mount solder thief pads for a through hole connector. The connector is two rows of 0.1" pitch pins and on waving there is often a bridge on the last two pins. To ease the layout overhead, we want to put the pads at either end of the connector to enable the PCA to be layed out/ reflowed either way round. Does anyone have any experience of doing this, what would the implications be of putting pads in front of the connector. Can you reccomend any side for the pads (through hole lands are 76 mil diameter)

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JohnW

#11550

Re: Design guidelines for solder thief pads | 7 May, 1999

| This is not strictly a surface mount query but any input welcome | I am thinking of using surface mount solder thief pads for a through hole connector. The connector is two rows of 0.1" pitch pins and on waving there is often a bridge on the last two pins. To ease the layout overhead, we want to put the pads at either end of the connector to enable the PCA to be layed out/ reflowed either way round. | Does anyone have any experience of doing this, what would the implications be of putting pads in front of the connector. | Can you reccomend any side for the pads (through hole lands are 76 mil diameter) | | Charles,

I've seen this done on a lot of boards but normally you would have the thief's behind the pin's so that the solder has somewhere to go typically the thief's are the same or slightly larger in diameter than the PTH holes and match the pitch of the offending connector. Another hint, I'vefound that actually removing the solder resist from between the connector pins on the bottom side ( execpt where there is tracking) helps as well. it's also got the benefit of eliminating the saltilite solder ball's yuou normally get at the pin's of the PTH leads.

JohnW

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