1008 Chip Inductor Land Pattern

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   Hello There,

in their specifications https://www.murata.com/~/media/webrenewal/support/library/catalog/products/inductor/chip/o05e.ashx page 130 (LQM2HP_EH), murata recommends a pad width (c) of 1.5mm which is considerably less than the width of the package/metalisation of 2.0mm. I tried to find any explanation for this, as I've never seen pads smaller than the width of the package.

For capacitors, murata also recommends making the pad smaller than the width, mentioning that this reduces stress: https://www.murata.com/en-us/support/faqs/products/capacitor/ceramiccapacitor/mnt/0008

Other manufacturers of similar-sized inductors propose more reasonable looking footprints: https://media.digikey.com/pdf/Data%20Sheets/Samsung%20PDFs/CIGT252010EH2R2MNE_Spec.pdf

Are there any IPC recommendations that would call for reduced pad widths as suggested by Murata?

Best Regards

Lukas

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Lukas Members Profile Send Private Message Find Members Posts Add to Buddy List New User Joined: 25 Mar 2021 Status: Offline Points: 3	Post Options Post Reply Quote Lukas Report Post Thanks(0) Quote Reply Topic: 1008 Chip Inductor Land Pattern Posted: 25 Mar 2021 at 5:25pm
	Hello There, in their specifications https://www.murata.com/~/media/webrenewal/support/library/catalog/products/inductor/chip/o05e.ashx page 130 (LQM2HP_EH), murata recommends a pad width (c) of 1.5mm which is considerably less than the width of the package/metalisation of 2.0mm. I tried to find any explanation for this, as I've never seen pads smaller than the width of the package. For capacitors, murata also recommends making the pad smaller than the width, mentioning that this reduces stress: https://www.murata.com/en-us/support/faqs/products/capacitor/ceramiccapacitor/mnt/0008 Other manufacturers of similar-sized inductors propose more reasonable looking footprints: https://media.digikey.com/pdf/Data%20Sheets/Samsung%20PDFs/CIGT252010EH2R2MNE_Spec.pdf Are there any IPC recommendations that would call for reduced pad widths as suggested by Murata? Best Regards Lukas



Tom H Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Joined: 05 Jan 2012 Location: San Diego, CA Status: Offline Points: 5718	Post Options Post Reply Quote Tom H Report Post Thanks(0) Quote Reply Posted: 25 Mar 2021 at 5:54pm
	The only consideration for a pad stack width to be smaller than the Terminal Lead is the Wave Solder process for bottom side mounted SMD packages. The IPC-7351 mathematical model includes the Terminal Lead Width and the Width Tolerance. This will always result in a pad size greater than the Terminal Width. However, this can be controlled by editing the solder joint "side" goals by making it a negative value.
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Lukas Members Profile Send Private Message Find Members Posts Add to Buddy List New User Joined: 25 Mar 2021 Status: Offline Points: 3	Post Options Post Reply Quote Lukas Report Post Thanks(0) Quote Reply Posted: 26 Mar 2021 at 11:41am
	Hello Tom, thanks for the insightful and prompt reply. I'll use the IPC-based land patterns for the murata inductors. Best Regards Lukas