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What to name Footprints for PCB Mounted Modules

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=685
Printed Date: 19 Nov 2024 at 9:40am


Topic: What to name Footprints for PCB Mounted Modules
Posted By: DaveCowl
Subject: What to name Footprints for PCB Mounted Modules
Date Posted: 16 Nov 2012 at 12:27pm

I have a need to add a land pattern for a small PCB module that will SM to the board with concave 'pins'.

I have seen this sort of thing before with things like WiFi and power supply modules, and there are through hole versions of some of these also.

In any case, what are these things 'formally' called, and what do folks call the land patterns?

I assume 'XXX_Manufacturer_Part' but I can't think of a nice unambiguous name for an attached PCB module...


Replies:
Posted By: Tom H
Date Posted: 16 Nov 2012 at 12:32pm
The IPC-7351 Footprint Naming Convention has a fundamental format -
 
Component Family + Pin Pitch + P + Body Length X Body Width X Body Height - Pin Qty
 
Example: MOD65P1200X1000X120-6
 

Posted By: DaveCowl
Date Posted: 16 Nov 2012 at 12:54pm
I guess 'MOD' would do. Covers a lot of evils.

A partially related question - what should one do about parts that want to be placed against or over the edge of the board?

This module wants to do that, but the issue also applies to parts like HDMI connectors where the body of the connector hangs over the board edge to fit in a housing slot snugly.

I am thinking with respect to courtyard and assembly outline, since I imagine that most CAD tools would highlight a violation for a part extending beyond the board (or even touching the board edge).

Is it preferred to reduce the outlines so that no violation is caused, or to keep the outline matching the part and tolerate or flag the violation that results?

Posted By: Tom H
Date Posted: 16 Nov 2012 at 1:00pm
All Connector Footprint names are MFR_PartNumber and all connectors should be stored in their own library to isolate them from the electronic packages.
 
MOD is too generic. I would stick to the ComponentFamily_MFR_PartNumber.
 

Posted By: AGONZ67
Date Posted: 26 Nov 2012 at 2:58pm

In Expedition PCB, the cell editor has an "allow cell overhang" checkbox in the package cell properties dialog box. I am not sure about other layout programs.

I keep my outlines around the entire body, and ignore or accept any violations.

On a separate thought, under member profiles what about an area to list CAD tools being used, PADS, Expedition, ORCAD, etc?

Posted By: DaveCowl
Date Posted: 26 Nov 2012 at 3:21pm

Thanks for the note. 

Certainly some connectors have a dimension that is supposed to be the board edge. I guess that could be worked in to the placement outline too (I believe that Expedition at least allows for more than one polygon in the placement).

For the most part I am using Mentor Expedition workflow but hope to widen my scope over time... :)


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