SN74LVC07A: Stencil pattern check

user4979899

Expert 3080 points

Part Number: SN74LVC07A

Hi Sir,

Could you please help to check below stencil pattern is suitable for SN74LVC07A?

Thanks

over 6 years ago

0 Clemens Ladisch over 6 years ago

Guru 316690 points

The datasheet refers to QFN and SON PCB Attachment (SLUA271), which says in section 4.4:

It is good practice to minimize the presence of voids within the exposed pad interconnection. Total elimination is difficult, but the design of the exposed pad stencil is crucial. The proposed stencil design enables out-gassing of the solder paste during reflow and also regulates the finished solder thickness. Typically, the solder-paste coverage is approximately 50% to 70% of the pad area. Designing an aperture that prints solder 1:1 with the exposed pad results in excessive metal volume that can "float" the part and cause opens and other manufacturing defects.

0 user4979899 over 6 years ago in reply to Clemens Ladisch

TI__Expert 3080 points

Does it means my pattern should be fine, correct?

0 Clemens Ladisch over 6 years ago in reply to user4979899

Guru 316690 points

No; this stencil pattern prints solder 1:1 with the exposed pad.

0 Karan Kotadia over 6 years ago in reply to Clemens Ladisch

TI__Genius 16735 points

Hi Anne,

I am not clear on your pictures. I believe you are showing the stencil design from the some appnote or datasheet from TI? If you want me to compare it to your board, I cannot because there are no measurements written on your board diagram.

Please clarify the images.

Thanks!

-Karan

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SN74LVC07A: Stencil pattern check