SN74AUP1G00: Manufacturing issue about footprint

Mark Chen52

Expert 5685 points

Part Number: SN74AUP1G00

Hi Expert,

Could you help to check below questions for customer?

Customer uses footprint (0.56mm)larger than our recommendation (0.42mm like blue mark in figure-1).From your point of view, what will the foot print like that effect on manufacture process??
It looks there is extension footprint design recommendation (like blue mark in figure-2) bases on original component for manufacture process. We are curious what purpose is for extension footprint design like that.

figure1:

figure2:

Regards,

Mark

over 1 year ago

0 Clemens Ladisch over 1 year ago

Guru 243090 points

1. This is just a minimum size. A longer PCB pad probably has no effect at all. You'd better ask the board manufacturer.

2. There is exposed copper from the side of the lead. The longer PCB pad allows a solder fillet to form. (Please not that exposed copper is possibly oxidized and is not guaranteed to wet during solder reflow. For automotive or other high-reliability applications where you want to do automatic visual inspection of the solder fillets, there are QFN packages with wettable flanks; see this blog post.)

0 Xuwen Liu over 1 year ago in reply to Clemens Ladisch

Prodigy 10 points

If the soldering quality condiftion for the leads located underneath the package mold compound is good but side wetting is not good and what will it effect??

0 Clemens Ladisch over 1 year ago in reply to Xuwen Liu

Guru 243090 points

Only the solder under the device matters. But it can be observed only with X-rays.

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SN74AUP1G00: Manufacturing issue about footprint