Landpattern calculator question

[Jackie Oh!]

Hi Tom,

I'm building landpatterns for 0603 wire wound inductors. I tried to get a landpattern from the calculator on this forum, but not sure which pattern I should use, chip or molded?

Also, I've run the comparitive landpatterns by our manufacturing person, here and he's concerned that the patterns offer no side or heel fillets in the landpattern calculator results. He's concerned about accuracy of placement. When the part is placed too far off the pad, will it float back to where it should be or will it be too light to do that, thus not getting a full attachment to the pad?

Thanks in advance for your answers.

Jackie Oh!

[Tom]

Jackie Oh!

Wire Wound Inductors are similar to Molded Inductors as far as determining the Land Pattern.

I'm attaching a document that we recieved from IPC regarding Toe & Heel Fillet sizes.

The land pattern calculator pad size takes into consideration the Maximum solder pad size. Most of your parts come in as Nominal pad size so this gives you extra land pattern solder area.

All the parts we've built so far that use this attached chart have worked flawlessly.
When you see:
8.6 Small Outline Transistors SOT-23
It refers to Chapter 8.6 in the current IPC-SM-782 handbook. The new updated IPC-SM-782 handbook with the new 3-Tier library system should be out any day now. It went to print last week.

[Jackie Oh!]

Tom,

Thank you for your prompt reply! I look forward to seeing the new IPC-SM-782 handbook.


Jackie Oh!