Using sophisticated algorithms, fiXtress optimizes PCB design by eliminating stress problems.
fiXtress interfaces with any leading EDA software. fiXtress provides the fastest, most accurate and highest capacity simulation engine to evaluate reliability, availability and maintainability early in the design cycle. It utilizes four analysis types - DC, AC, Bus simulation and accumulation.

fiXtress quickly identifies design errors and provides a detailed and comprehensive analysis of the PCB - including calculation of the stresses applied to all components - discrete, analog and digital ICs. As these calculated stresses are compared to de-rating curves, fiXtress highlights over-stressed and under-stressed components. Based on this information, fiXtress accurately predicts the PCB MTBF and indicates the components most likely to fail.

 

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Stress De-rating Analysis:

PCB designers try to design their circuit for specific voltage, current and threshold values for power dissipation, output current, junction temperature and frequencies. Being given these rated values, the designer chooses to adjust the design to minimize the stress on the components. This practice, known as "de-rating", is a technique through which either stresses acting on a part are reduced, or the strength of that part is increased by replacing it with a component with higher rated values. This analysis is usually performed by hand, and summarized in a spreadsheet format. fiXtress, however, can determine the applicable stress automatically under any EDA tool. Performing this analysis before the component’s placement and the manufacturing of the PCB, assures the proper component selection and saves redesign time, maximizing the circuit performance and reliability parameters.


Interface Analysis:

fiXtress also performs interface analysis, assuring that each interface meets the output and input requirements to perform a given function. In digital circuits, this means that every digital/analog output will be matched by a compatible input, and that the fan-out requirements are met. As an example, an interface analysis might be used to assure that FPGA pins are fully enhanced and also fully depleted in order to assure full circuit performance.


Electrical Stress:

To measure the electrical stress on each component in the design phase of an electrical circuit is not an easy task. Many parts have several parameters which must be assessed, including their electrical relation to adjacent components and to the entire circuit. For example, for a capacitor, working voltage as well as ripple current must be determined. For a resistor, it is power consumption as well as power-peak or voltage. For diodes, it may be reverse voltage, junction temperature, forward current and AC effects. The electrical stress information for all electrical circuit parts are fed into the fiXtress tool, which provides accurate power dissipation and thermal heat information on each component to meet reliable stress calculation and design requirements.

Optimal Parts:

Enables to select the optimal rating of each component: for an overstressed component to select a higher rating value (larger physical size generates higher reliability), and for an under stressed component to select a lower rating value (smaller physical size saves PCB room).


Design to Reliability:

Unlike standard Parts Count analysis, that uses a generic default for the stress applied to each component type, fiXtress uses the actual stress applied to each component. Components in equipment may not always operate under the reference conditions (parts count). In such cases, the real operational conditions will result in failure rates different from those given for reference conditions. To be able to follow accurate design criteria, fiXtress uses actual temperature and actual electrical stress imposed on each component. fiXtress increases system design reliability by using a four-stage analysis:

Performing comprehensive verification of circuit physical faults such as shorts and disconnections.

Complete analysis of the entire system stress characteristics, including temperature, frequencies, voltage, current, and power developed on each component and pin.

Comparing the stress results to de-rating curves to identify design faults. Recommendations to solve the stress problem are provided.

System MTBF prediction using a choice of industry standard methods to meet various environment requirements.


Key Benefits:

• Simulates digital, analog, RF and passive components including high frequency Bus-Simulation.
• Prevents PCB failure by warning which components are over stressed due to power dissipation or violation of voltage or current limits.
• Reports under stress components.
• Validates PCB predicted MTBF result against the MTBF design criteria.
• Allows designers fine tune component rating values faster than a trial and error testing to meet exact power performance goals.
• Allows electronic circuits to be simulated for detecting early design problems.
• Problems can be identified in an early stage when their correction is easier and less costly.
• Allows a comprehensive PCB faults verification
• Makes it easy to define any component in the circuit simply by entering available data from the component’s data sheet, without the need to build time-consuming complex models, like SPICE.
• Simulates and detects fan-out for IC's and connector current problems.
• Accelerates PCB design cycles for rapid time to market.
• Can be used and combined with any EDA tool to support advanced PCB analysis.
• A short-term training, easy-to-use software.

fiXtress Advantages Over Traditional Analysis:

fiXtress can handle large PCB's with thousands of components, including FPGAs with more than 1,000 pins each, not only analog circuits. fiXtress provides the results in a tabulated form for easy de-rating analysis. SPICE analysis has traditionally been used in areas such as IC design and power analog devices, which requires a high level of accuracy and wave view. However, in the PCB and systems domain, the SPICE method has several disadvantages over fiXtress for both the PCB designers and the device vendor.
SPICE normally simulates a model of a circuit at transistor level. These simulations must contain detailed information about the circuit and process parameters. Most IC vendors consider this type of information proprietary and resist making their models available to the public. Contrary to the SPICE models, fiXtress uses standard data sheets available to the public with no need for proprietary information. SPICE simulation accuracy is typically very good. However, simulation speeds are particularly slow for transient simulation analysis, which is most often used when evaluating power dissipation and signal integrity performance. fiXtress simulation speed is much faster than SPICE simulation, and allows what-if analysis very quickly.

Finally, not all SPICE simulators are fully compatible. Often, default simulator options are not the same in different SPICE simulators. Even though there are some very powerful options which control accuracy, convergence and the algorithm type, any options which are not consistent may cause poor correlation in results across different simulators. Moreover, because of the different variants of SPICE, these models are often incompatible between simulators; thus models must be extracted for a specific simulator.

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