Recreating a component, from scratch or from existing silicon, ensures continuity of supply and eliminates the danger of purchasing counterfeit parts
Obsolescence problems caused by using custom off the shelf (COTS) parts in long life systems have increased dramatically over the last few years and the grey market has become flooded with counterfeit parts.
Many organisations that work in the aviation, space, and defence industries now include counterfeit parts prevention processes within their contractual terms. Furthermore, AS9100C introduces an important clause, listed as 7.1.2 risk management, designed specifically to tackle this growing problem.
Using AS9100 revision C qualified vendors is a useful way of protecting yourself from the danger of inadvertently purchasing counterfeit parts. Unfortunately even the most rigorous quality systems cannot eliminate the risk completely.
Build a solution
One important method used to achieve continuity of supply of critical parts is to recreate the component, or it’s logical function, to engineer a drop in replacement for the obsolete item. This means that expensive and time consuming redesign and requalification requirements are kept to a minimum.
Taking the recreation approach also eliminates the possibility of using counterfeit parts and can guarantee the availability of critical components for the entire life of the project.
There are various ways to recreate semiconductor components, depending on the level of obsolescence, and it is even possible to recreate the logical operation of a group of parts using a field programmable gate array (FPGA) device. Very complex parts, such as the Intel 80486 processor, can be emulated by providing only the elements that are actually used in the target design.
Another innovative technique, where the original semiconductor is freely available but in the wrong package, is to extract the die and repackage it. There are now cost-effective, high-volume extraction techniques to remove silicon die from any plastic package and re-assemble them into any other plastic or hermetic ceramic JEDEC, metal can or custom package. Test data shows that parts manufactured from harvested die can be more reliable than the original parts.
DIY instructions
Here are the most popular methods of recreating obsolete semiconductors:
1) FPGA emulation of logic
Method: Replace obsolete FPGA and/or other discrete parts with a new lead-free FPGA. This can be used to recreate Intel and other x86 processors, including the 80486.
Useage: When the original parts are no longer available and can be recreated in logic.
2) Reverse engineering designs from a single part
Method: Re-create semiconductor components from a single sample.
Useage: When some original parts are available, but the original designs are not.
3) Die extraction and repackaging
Method: Extract die from readily available commercial parts, repackage, up-screen and test.
Useage: When the original part is available, but in the wrong package.
4) Up screening of lower specification parts
Method: Test readily available commercial products and select those which meet higher military specifications.
Useage: When commercial parts are available that may meet a higher specification.
5) Re-creation using existing die
Method: Purchase bare die, package and test.
Useage: When the original die is available unpackaged or can be remanufactured.
Electronic component obsolescence is a fact of life that isn’t going to go away, but with careful planning and a trusted supply partner, qualified to AS9100 revision C, it is possible to manage the risks and costs down to an acceptable level and avoid the need to redesign and re-qualify long life systems.
Force Technologies’ white paper ‘The current state of the art for managing electronic component obsolescence‘ can help assess the various options.
www.force-technologies.com