Hi,
We got a 0.5mm pitch QFP144 from Altera with the below lead width specs.
min. lead width = 0.17mm nominal = 0.22mm maximum = 0.27
What's the best pad or land width for the above?
This is what our designer used.
Land Width = Component Lead Width + 20% of that Component Lead Width
The problem is that some of the QFP leads are easily detached using a small amount for push force using a thin pick. I found out that the solder joint is not very strong because there is no solder fillet on the left and right side of the lead and the possible cause, which is very visible, is that the lead width is one-to-one with the land and in some cases you can no longer see the land / pad.
from the above land width calculation, which among the lead width value will he need to base his Component Lead Width, minimum ? nominal? or maximum? He told us that he used the nominal but it seems like we are getting QFP's with the maximum lead width. What's the best Land Width for the above manufacturer's lead width specification? Is IPC's Land Design Standard a best reference?
Thanks and regards,
Thanks to you DaveF in advance.... :=)
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