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Circular Connector Origin

Printed From: PCB Libraries Forum
Category: Libraries
Forum Name: Altium
Forum Description:
URL: https://www.PCBLibraries.com/forum/forum_posts.asp?TID=3580
Printed Date: 24 Nov 2025 at 12:25pm


Topic: Circular Connector Origin
Posted By: AGONZ67
Subject: Circular Connector Origin
Date Posted: 24 Nov 2025 at 8:09am
What is the standard for circular connector origins? 

Is there an IPC spec that specifically states pin one or centroid of body?


Replies:
Posted By: Tom H
Date Posted: 24 Nov 2025 at 8:23am
Normally, the footprint origin is the Center of Gravity. 

However, some designers put the origin on Pin 1. We did this in the 1980s and 90s to keep all the pad locations on a 0.10" grid to make routing traces easier. 

But then the metric system came along and gridless routing. 



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Posted By: AGONZ67
Date Posted: 24 Nov 2025 at 8:36am
Does IPC specifically state a location? 

I don't have the spec handy, but a search produces the following results. "According to the According to the IPC-7351 standard, the origin for a circular connector's land pattern should be at the centroid (center) of the part's body." 

We are about to have this discussion and would like to know if there are established IPC specs stating something to the effect of, "origin of through hole circular connectors shall be 'pin one', or 'centroid' ?

Posted By: Tom H
Date Posted: 24 Nov 2025 at 9:42am
I've never heard of IPC providing any guidance on land pattern origin or drafting outlines for silkscreen (IPC says no silkscreen is preferred), assembly, component, terminal, origin target. 

IPC left this up to the PCB designer preference. 

However, most assembly pick & place machines use the center of gravity for the origin. 

If a PCB designer places the origin for the 14-pin DIP footprint, then the assembly shop must take the time to calculate the center for their pick and place line. This is very time consuming.

You should discuss footprint origins with your assembly shop. You provide the X,Y coordinate list for all the footprints in your PCB layout. What does assembly prefer?



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