In-production electronics testing: news and technology review
This week, on May 1-2, there is a big event devoted to the design and most aspects of electronics manufacturing—Del Mar Electronics and Manufacturing Show 2019 in California. So we have prepared for our readers a review of new and the most popular methods of electronics testing at the production site.
One of the main novelties of this year's show is the presentation of large-scale sub-nanovolt testing technology for small-signal discrete devices by Linear Integrated Systems. It will enable individual screening up to tens of thousands of small-signal discrete components to levels below a billionth of a volt of noise (nV/√Hz). This is a highly specialized technology for the lowest noise signal chains and the mass production of devices with specific noise levels.
As for more common technologies, let's consider the most popular testing methods that can be used to check the quality of a variety of electronic devices in the field of multimedia, consumer, automotive, etc.:
1. Automated vision inspection implies automatic optical inspection (AOI) or automatic X-ray inspection (AXI). This pre-testing method is used by all contract manufacturers during various stages of PCB mounting.
2. In-circuit testing (ICT)—analog and digital—allows checking PCB connections and components in case of large-scale production.
Analog ICT helps to detect a large number of assembly defects, such as short circuits and breaks, discrete component value, correct installation of microcircuits, etc. This process requires complex, expensive equipment, and technological preparation.
In digital in-circuit testing, digital chips are checked for compliance with the truth table, but this method has a number of difficulties in implementation.
3. Peripheral and boundary scan includes JTAG testing and helps to control the quality of installation and reject devices before the functional testing. The main advantage of the technology is an opportunity to test devices with limited access to chip outputs in BGA, COB and QFP packages.
Nowadays software tools for JTAG testing can automate the process using data schematics from CAD which make this method more available.
4. Functional testing (FCT) is a checking assembled devices for execution of a given functionality and compliance with parameters. FCT can be carried out both in manual and automatic mode. Of course, mass production specialists advise to reduce manual labor to a minimum.
In practice, the best variation of testing technologies at the production site is an optimal choice of the method or a set of them taking into account the scale of production, the complexity of the product and special requirements for its quality. This choice allows achieving a minimum time of testing with a maximum result. Combination of the parameters will be unique for each new project.
Feel to contact us if you need help choosing the best combination of test methods, we will be glad to share our knowledge and experience in QA of electronic devices.