Uncovering Assembly Problems of High-Speed PCBs


Reading time ( words)

High-speed PCBs have become much more common during the past five years. However, special challenges arise due to unanticipated high-speed issues. Some relate to manufacturing or processes, while others are pure component- or fabrication-based. In particular, highly complex, highly integrated components like FPGAs need close scrutiny. Also, it’s important to note that PCBs may use mixed materials like Rogers and FR-4 cores in order to incorporate those high speeds.

The mixed-material board may need pre-preg special processing and temperature treatment compared to conventional FR-4 boards. In such cases, extra care must be applied to watch for certain manufacturing aspects. For example, high-speed boards might pass at certain lower spectrum speeds, but begin failing at certain other higher speeds. However, when it comes to regular investigation, those same boards might pass all the run-of-the-mill tests like flying probe, functional tests and ground-to-power short tests.

It becomes worrisome when these boards fail at certain high-speed level bands. Investigation as to the reason(s) why they fail include checking out the process and dissecting it step-by-step and scrubbing the bill of materials (BOM) all the way from A to Z to make sure there are no issues during verification testing.

The high-speed board may be perfect when it comes to BGA assembly. All the balls properly collapse; all the thermal profiles are accurately determined and performed. All soak temperatures, pre-heat, soak and cool-off periods fall within manufacturer limits and ranges. Yet, this high-speed board fails at high speed at the time of system functional level testing in the system.

Read the full column here.


Editor's Note: This column originally appeared in the February 2014 issue of SMT Magazine.

Share

Print


Suggested Items

Building A Better, Brighter LED Headlamp with Top-Side Alignment Process (TAP)

02/10/2021 | Glenn Farris, Universal Instruments Corp.
An emerging trend in the automotive industry is the adoption of advanced LED headlamp lighting systems. These systems drive challenging placement requirements for LED packages. In this paper, we will review these unique challenges and discuss a novel approach to high-accuracy placement of LED packages enabling a scalable production solution.

How to Benefit From Robotic Soldering Processes

10/28/2020 | Pete Starkey, I-Connect007
Webinars are in vogue! But in Pete Starkey's experience, the master of the technical webinar with many years’ experience of delivering first-rate events is Bob Willis—electronics assembly specialist, soldering expert, and provider of training and consultancy in electronics manufacture. Here, Pete recaps Bob’s presentation on the upcoming robotic soldering experience.

SMTA Additive TechXchange Keynote: An Outlook on Advanced PCB Fab

10/20/2020 | Pete Starkey, I-Connect007
Organised as a virtual event by Lenora Clark of ESI Automotive and Tara Dunn of Omni PCB, SMTA’s Additive TechXchange addressed additive technology specifically in the context of the electronics industry. Pete Starkey details the keynote presentation, an outlook on advanced printed circuit board fabrication, from Jeff Doubrava, managing partner at Prismark Partners.



Copyright © 2021 I-Connect007. All rights reserved.