The Survey Said: Designing Around Missing Data

Estimated reading time: 1 minute

One of the best tools we have for keeping our fingers on the pulse of the industry is the reader survey. When we want to find out what’s going on, we just ask. Fortunately, our readers are not a shy bunch of folks. They don’t mind sharing—the good, the bad, and the ugly.  

In a recent survey, we asked our PCB designer readers, “What missing information or data (impedance requirements, library data, etc.) do you find yourself having to ‘design around’?”  

The replies were all over the place; I don’t think any two respondents said the same thing. Here are some of more illustrative replies we received, edited slightly for clarity. Do these comments reflect what’s happening at your company? 

1. Those are the things that I demand before beginning.
2. Usually several pieces of PCB specific data are missing or falsely specified, especially for impedance requirements.
3. Provisioning for functional test.  We often have to wait for the CAD office to approve new footprints, and for commodity management to approve part suppliers.
4. Quite frankly, we insist that we know fairly early in process, but getting rules/feedback from vendors is very difficult. Vendors don't seem to be able to articulate their own rules or capabilities and it varies significantly per facility if they have multiple facilities.
5. Impedance data—cost-effectiveness depends on the board material that is stocked by the board house. Workaround: We specify tracks and impedances, and permit board house to adjust the CAM files as needed. Assembly requirements: What's the permitted height of components close to the rails? What's the shadow area around high components? Library data is usually a non-issue: we simply don't trust outside sources for any library data.   

The I-Connect007 Research Team regularly polls members of the electronics manufacturing industry on trends in the industry so we can bring you topics that you care about.