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Standard Chip Package Case Codes & Dimensions

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Tom H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Tom H Quote  Post ReplyReply Direct Link To This Post Topic: Standard Chip Package Case Codes & Dimensions
    Posted: 07 Feb 2022 at 10:01am
IPC-7351B contains the 3-Tier Density Levels for Land Patterns. 

However, that document is 12 years old and out of date and it took information from the 1987 IPC-SM-782 which is obsolete.

The solder Joint values are way too robust for today's technology. 

Footprint Expert solder joint goals are derived from IPC J-STD-001 standard as it's the main standard that all other standards are built upon. 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote AnonAnon Quote  Post ReplyReply Direct Link To This Post Posted: 07 Feb 2022 at 5:41am
Hi Tom,

Please excuse me if you've answered this a thousand times but I'm looking to find which standard defined the "Least" and "Most" limits for each footprint. I can see IPC-SM-782 defines the nominal and references equations in a section 3.3? I am happy to purchase the standard but wanted to ensure it contained the correct information before I purchase.

Do the IPC standards only provide the nominal and one has to calculate the limits?

Kind regards,

David
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Tom H Quote  Post ReplyReply Direct Link To This Post Posted: 08 Sep 2021 at 8:32am
Read the User Guide in the main installation folder under "Documents". 

  • Charter 1 Footprint Expert Console Options
  • Charter 2 Footprint Expert Calculator Options - Pad Stack Rules
  • Charter 3 Footprint Expert Calculator Options – Drafting
  • Charter 4 Footprint Expert Calculator Options – Fiducials
  • Charter 5 Footprint Expert Toolbar Icons and Menu Options
You cannot edit the program Master Options. You need to create your personal option files (as many as you want). 

Select File > Save As > Your Master Options .opt

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Post Options Post Options   Thanks (0) Thanks(0)   Quote phil.holden Quote  Post ReplyReply Direct Link To This Post Posted: 08 Sep 2021 at 5:26am
Hi Tom,

For my Enterprise Edition CLOUD Licensed the options under Pad Stack Rules are 'greyed' out. Does this mean that i am unable to control this globally? 
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Tom H View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Tom H Quote  Post ReplyReply Direct Link To This Post Posted: 07 Sep 2021 at 9:08am
To get 3 or more passive packages to fit into the same Footprint, find parts with the same dimensions and tolerances. If the package dimensions are the same but the tolerances are different, then round the tolerances off so that they are all the same. 

Rounded Rectangle Pad Shape: You should change your Maximum Radius from 0.25 to 0.15 or 0.10 or something smaller. 

Change this setting in "Tools > Options > Pad Stack Rules > SMD Corner Rounding > Corner Radius Limit". 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote phil.holden Quote  Post ReplyReply Direct Link To This Post Posted: 07 Sep 2021 at 4:08am
As is common procedure, especially during these times with supply-chain issues. We try and specify x3 MPNs for all of our passive devices. 

As there could be 3 substituted parts fitted all with differing terminal lengths. How am i best addressing this when creating a passive library? 

This is much less of a problem for active parts and connectors that are less 'interchangeable'. 

Thanks

In addition to the above. I have noticed that the terminals sometimes overhang the pads when using 'rounded rectangle'. In your opinion, would this be a problem? 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Tom H Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jul 2021 at 8:47am
You need to attach a link to a PDF file zipped or a URL link to the datasheet would be better. 

Then we can post the Proteus footprint. 

Are you using the Free V2021 Footprint Expert Pro for Proteus? You could create the footprint in a couple minutes. 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote lladam Quote  Post ReplyReply Direct Link To This Post Posted: 02 Jul 2021 at 6:26am
Hi,

How to make a Proteus library part of MEGA2560 Pro Mini, or where can find one please.

Because the board too small to put many pins on.

Thanks
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Tom H Quote  Post ReplyReply Direct Link To This Post Posted: 25 Mar 2021 at 11:59am
Use the mfr. recommended pattern for this new upcoming component family. 

Some manufacturers use a periphery solder joint goal and other use a Toe, Heel and Side pad stack. 

This is a new Terminal Lead form that has not been fully tested by the world standards like IPC-J-STD-001 for solder joint acceptability. 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Arun7290 Quote  Post ReplyReply Direct Link To This Post Posted: 25 Mar 2021 at 11:52am
Hi Tom,

Thanks for the reply. Can we use the above listed package sizes for Wraparound parts as well in the same case code? 

Because It is mentioned that the above case code dimensions are only for Standard Chips. 

And I am working on some wraparound packages of the standard case code. 

Can we use PCB library expert for footprint creation for these parts? 

Or Is it better to follow the Manufacturer recommended land pattern?


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