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Enlarge Pads on Corner SSOP Package Pins.

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Enlarge Pads on Corner SSOP Package Pins. | 23 August, 2011


Any one known if it is really benificial to enlarge the end pads width of SSOP package ? does this really solve any cold solder issue ?

facing some cold solder issues on one design only !

Please suggest !

Thanks alot in advanced..!

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Enlarge Pads on Corner SSOP Package Pins. | 29 August, 2011

Enlarging the "End Pads" is normally done to help accomodate the Wave soldering process... works as solder thief to help eliminate bridging on the last 2 pins to cross the wave. It is reasonable to assume that, if you are seeing cold solder due to flux burn-off or insuffiecient flux due to small aperture openings, enlarging the pad would reduce cold solder deffects by increasing the amount of flux applied in the solder deposit and increasing the amount of time to "burn off" the flux... This would only apply to the pads that have been enlarged.

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Enlarge Pads on Corner SSOP Package Pins. | 29 August, 2011

We agree with JAX. Changing the pads on your board as you describe won't do shit.

Possible solutions to a cold solder connection problem include: * Raise the peak temperature to be high enough to reflow the material thoroughly. * Select a solder paste formulation that better matches your application. * Prevent vibration of assembly during and immediately after reflow. * Accelerate the cool down rate after reflow. * Check the alloy analysis for high levels of contaminants.

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Enlarge Pads on Corner SSOP Package Pins. | 7 September, 2011


What is telling you that you have cold solder? You do not give much info.

My QA/QC love this term to describe a multiple of issues. They are usally very wrong.

If this is a reflow process and it just affects one part? An SSOP is not likley to be an issue unless there are some significant thermal issues with the location (ground planes, heavy adjacent parts, old crappy cal rod oven)

Have you actuly done a reflow profile?

What is the eveidence for cold solder? Non wetting, bumps on the end of the pads(ENIG board, perfectly normal, remeber you do not need a toe at all)

Look at the wetting on the heal and the sides of the leads, is there good wetting?

have you eliminated any issues with solderability?

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