Up-Screening Issues & Tips

It happens, especially when you’re working with older parts.  When you just can’t find an electronic component with the right manufacturer specs to do the job, either at all or at anything but an exorbitant price, then it’s time to consider up-screening parts you either have in stock or can purchase. “Up-screening” is testing for the purpose of documenting device performance to higher specs, including wider temperature ranges, as compared to original manufacturer drawings. Up-screening is made possible by the fact that semiconductors and other active and passive components can often operate above and beyond at least some of their official specifications.

Common scenarios in which up-screening may contribute to a viable solution include:.

• An obsolete component that is no longer available is required to maintain, repair or produce a legacy part or system and thus you seek to substitute another part.
• A customer is looking for a military or industrial version of a COTS item so you need to enhance performance or environmental tolerance.
• Part selection to weed out marginal product via burn-in to help ensure reliability.
• To address a design issue in which a part needs to perform at a higher level or withstand a higher stress level and thus needs to meet higher specs or be replaced.

ACT can test and characterize EEE parts including passives, logic, analog and discrete devices to a source control drawing or to comply with other (for example, military) specifications. Parameters to which ACT engineers and technicians can perform up-screen testing include: temperature, voltage, current, timing and frequency.

Before you embark on an up-screening project, here are a few suggestions from the staff at ACT:

• Prior to buying a large stock of parts that you hope to up-screen or perform part selection on, consider testing a small sample to gauge whether or not you’re likely to achieve the desired outcome.
• If you need assurance that a device can operate reliably at a higher or lower temperature, then keep in mind that temperature can affect device speeds and voltage levels. To avoid problems, we advise additional testing of all parameters that may be affected.
• Although authentic new parts should perform to manufacturer specs every time, these same parts may outperform these specifications to varying degrees and thus may not consistently reach the level desired. The smart move is to plan for some fall out.
• Before embarking on burn-in or other stress testing, you might want to confirm that any anticipated reduction in lifespan is acceptable.