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AVX TurboCap Footprint

Printed From: PCB Libraries Forum
Category: PCB Footprint Expert
Forum Name: Questions & Answers
Forum Description: issues and technical support
URL: https://www.PCBLibraries.com/forum/forum_posts.asp?TID=42
Printed Date: 21 Nov 2024 at 11:17pm


Topic: AVX TurboCap Footprint
Posted By: RLS2004
Subject: AVX TurboCap Footprint
Date Posted: 27 Apr 2012 at 11:45am

What should the heel, toe and side solder joint dimensions be? AVX Turbo Cap, J style leads, ST205C series High_CV SMPS capacitor. Link to data sheet:

  http://www.avx.com/docs/Catalogs/turbocap.pdf" rel="nofollow - http://www.avx.com/docs/Catalogs/turbocap.pdf



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RLS2004


Replies:
Posted By: Tom H
Date Posted: 27 Apr 2012 at 12:12pm

You need more than Toe, Heel & Side dimensions to calculate the Pad Size and Spacing.

These 7 factors are used to calculate the optimum Land Size

Component Body Tolerance – ± 4 Mil (0.1) thru ± 12 (0.3)
Component Terminal Tolerance – ± 8 Mil (0.2) thru ± 20 Mil (0.5)
Fabrication Tolerance – ± 2 Mil (0.05 mm)
Placement Tolerance – ± 1 Mil (0.025 mm)
Land Size Round-off – ± 1 Mil or (0.01 mm)
Land Spacing Round-off – ± 1 Mil or (0.01mm)
Solder Joint Goals for Toe, Heel and Side

The new IPC-7351 Footprint Calculator will be available for Free download with a login or registration requirement on May 21 on the front page of the upcoming http://www.pcblibraries.com" rel="nofollow - www.pcblibraries.com website.
 
Also, the "J Style Leads" are really "Outward L Bend" -
 
 
The new upcoming 2012 IPC Footprint Calculator is component lead based to handle every component family.
 
But for the time being here is the info you asked for -
Toe = 14 mils (0.35 mm)
Heel = 14 mils (0.35 mm)
Side = 2 mils (0.05 mm)
 
If you use mils, round-off the pad size and pad center spacing in 1 mil increments.
 

Posted By: RLS2004
Date Posted: 27 Apr 2012 at 12:56pm
Hi Tom,
Thanks for the reply.
Did you note that the "J style leads" on this part bend UNDER the component. Looks similar to an SOIC but the leads bend under the part. Old IPC-SM-782 page 10 figure 3-2 shows a "C" bend style of lead  that looks similar to this part. What 7351 component family would you recommend for this part?
 

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RLS2004

Posted By: Tom H
Date Posted: 27 Apr 2012 at 1:33pm
My mistake, but the same solder joint goals for Toe, Heel and Side apply.
 
IPC-7351 uses "Component Families" to break down solder joints.
 
The new IPC Footprint Calculator uses "Component Leads" instead.
 
There are 150 different standard component families and unknown number of non-standard component families, but there are only 21 different Component Lead Styles.
 
What do these Component Families have in common?
Ceramic Flat Pack (CFP)
Ceramic Quad Flat Pack (CQFP)
Small Outline Diode (SOD)
Small Outline Transistor (SOT23, SOT223, SOT343 & SOT143)
Small Outline Package (SOP)
Transistor Outline (TO or DPAK)
 
They all have a Gull Wing lead form. So why apply the same rules to 9 different component families when it's better (more efficient) to apply rules to a single Lead Form.
 
We still have component families in the Footprint Calculator, but the "Preference Rules" are much simpler when the rules are applied to the "Lead Form".
 


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