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Defense Microelectronics Activity. Rapid Obsolescence in Recent Designs – Is There a Solution?. Keith Bergevin Senior Design Engineer 4234 54 th St., Bldg 620 Sacramento, Calif. 95652-1521 Phone: (916) 231-1652, Fax: (916) 231-2818 email: bergevin@dmea.osd.mil http://www.dmea.osd.mil.
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Defense Microelectronics Activity Rapid Obsolescence in Recent Designs – Is There a Solution? Keith Bergevin Senior Design Engineer 4234 54th St., Bldg 620 Sacramento, Calif. 95652-1521 Phone: (916) 231-1652, Fax: (916) 231-2818 email: bergevin@dmea.osd.mil http://www.dmea.osd.mil
Presentation Roadmap • Why are recent generation designs highly susceptible to obsolescence? • What options are available? • ASIC redesign methodologies • Ensuring a complete solution
Why are Recent Generation Designs Becoming an Enormous Problem? • Consist primarily of ASIC devices • Virtually sole source • Custom ASICs have limited supply – typically one fabrication run • Unique design eliminates component supply “sharing” • Very difficult to redesign • High density, complex devices • Design documentation is critical but often deficient • No correlation between part numbers and design functions
What Options are Available? • Direct FFF replacement? No! • ASICs perform specific functions – with the exception of FPGAs, finding an equivalent device number will not suffice • Exhaustive database search for second source? No! • Custom designs render search of other programs for equivalent devices useless • The only remaining option – various levels of redesign • Component, board, or system redesign
The Dilemma of ASIC Redesign • Recent program upgrades experienced obsolescence within two years – why go through the same process? • Valid argument - Without a change in approach, the solution will again be temporary • Insufficient data exists on the obsolete module, resulting in prohibitively expensive redesign proposals • Unfortunately, this is a common occurrence • Where does this lead us?
The Prudent Way Out of This Mess • The Previous slides have established the following: • The “quick & easy” solutions do not exist • A redesign approach is the only remaining option • Insufficient documentation results in difficult and costly redesigns • Option (2) was recently implemented without eliminating obsolescence • An ideal solution would include the following: • Tools and methodologies to reduce NRE redesign costs • Implement designs with better DMS immunity • Realize obsolescence is inevitable - apply methodologies that enable device re-targeting without costly redesign
DMEA’s ASIC Redesign Approach • Apply cutting edge tools & methodologies to accurately characterize legacy component • Scrutinize components to select least vulnerable • DMEA flexible foundry • Select components commonly used by industry to provide greater assurance of future availability • Provide complete, verifiable, vendor-independent documentation • VHDL, Verilog, EDIF, etc.
Developing an Accurate Redesign Specification – AnExtremely Difficult Requirement • Many obsolete ASICs contain up to 1M gates • ASIC devices perform unique functions • Vendor data sheets provide no functional descriptions • Specific component number provides no functional information • Package size, type, & pin-out vary greatly • Virtually impossible to have 100% test coverage • Board level test programs typically cover small subset of ASIC functions
DMEA Developments in the Specialty of Device Characterization • Hardware Modeling: A novel approach to ASIC redesign • Method of interfacing actual legacy silicon into simulation environment • The device becomes a logic model which is instantiated into the VHDL design for simulation • Enables creation of a fast, efficient and 100% accurate simulation model of the legacy device • Enables direct functional comparison of Legacy vs. redesigned component
Hardware Modeler Configuration DeviceAdapter HardwareModeler High-end Workstation
Prototype Development 1. Synthesize VHDL model to Field Programmable Gate Array (FPGA) 2. Migrate test vectors to board or chip level tester • Vectors translated from VHDL test benches 3. Apply test vector set to legacy device and FPGA prototype 4. Compare vector output files 5. Test prototype at customer facility
Fabrication Options • DMEA Flexible Foundry • Form, fit, function replacement via commercial devices • Re-Target VHDL to ASIC with matching footprint • FPGA to ASIC conversion • FPGA die repackaging • Replace legacy device with FPGA • Low-cost approach for small quantities • May require modification to board layout
Summary • Recent generation designs are extremely susceptible to obsolescence • Database and other tracking tools largely ineffective in finding replacement devices • DMEA is maintaining a leadership role in applying tools, techniques, and expertise to combat obsolete ASICs • Adhere to sound DMS redesign practices to ensure long term cost-effective solutions