Systems/Circuits Reliability Engineering

Bastion Technologies has quickly become one of the preeminent organizations supporting reliability and mission assurance at the systems and components level for both government and industry partners.

Bastion offers a complete suite of reliability engineering services, including the following:

Parts Stress Analysis and Derating

Most failures in an electrical/electronic device or system of components are a direct result of subjecting the components to an overstress condition.

Electrical Parts Stress (EPSA) and Derating Analysis is a detailed analytical report of the applicable voltage, current, power, and thermal stress on each individual element within a system or component. Both nominal and worst-case end-of-life (EOL) stress calculations are provided, with the worst-case results using EOL component tolerances, worst case environment, and worst-case operating conditions (input and loading). Transient stress conditions such as startup, current limit, short circuit, and other fault conditions are also assessed.

The calculated quantities are compared against a set of derated component ratings. The nominal stress ratios (nominal value/rating) are computed for use in the Reliability (MTBF) analysis. The derated stress ratios are also computed.

Worst-Case Circuit Analysis

Worst Case Circuit Analysis (WCCA or WCA) is an integrated, cost-effective means of design analysis – ensuring that potential defects and deficiencies are identified and eliminated during design, development, integration, test, and delivery. It has become a critical component of rigorous design engineering and related project/systems risk management.

It is critical that WCCAs are conducted during the design and development phases of the system, utilizing mathematical analysis, simulations/models, and verified against actual engineering hardware, all the while tracking system changes, updates, and revisions.

A WCCA is typically performed by hand, and summarized in a report and spreadsheet format. Software simulations or other mathematical models are often used to determine the applicable stresses on the electrical components and systems. Bastion is highly proficient in utilization of PSPICE (Personal Simulation Program with Integrated Circuit Emphasis) and other SPICE circuit simulator applications for simulation and verification of analog and mixed-signal circuits.

Essential elements of WCCA include:

• Serves to validate acceptable operations throughout the entire system lifecycle, through the worst-case combination of anticipated conditions [Worst Case Extreme Value Analysis (EVA)]
• Defines Critical Components and Spec Control Drawing (SCD) Limits
• Provides Acceptance Test Procedure (ATP) Limits
• Defines the need for and Range of Select-At-Test (SAT) components
• Improves Reliability through (Electrical) Parts Stress and Derating Analysis
• Identifies design concerns which during test, alignment, and use, could result in circuit damage or premature degradation.
• Baseline of system models and simulations, correlated against engineering hardware to determine part stress margins, and EOL/BOL product operating specifications.

Worst Case Circuit Timing Analysis (WCTA)

The Worst Case Timing Analysis (WCTA) portion of the WCCA analyzes the timing of devices and signal paths under worst case conditions.

Signal Integrity Analysis

Bastion provides Signal Integrity (SI) expertise for all types of digital circuitry, especially applicable to space and high-reliability applications. We provide validation of board layout and interconnect performance. Signal integrity (SI) analysis is an essential part of evaluating board designs.

Signal integrity analysis consists of a series of analytical tasks intended to verify reliable communication between all digital circuits on a board. Bastion utilizes HyperLynx for high-speed design analysis.

Single Event Analysis/Radiation Analysis

Bastion provides Single Events Analysis (SEA) focused on radiation effects analyses for space, avionics, and ground systems, including ICs and all types of circuit applications.

Analyses include:

• TID Impact – Total Ionized Dose degradation of semiconductor devices and different types of materials results from a low and steady flux of energetic electrons and protons that exists in the natural space environment
• PD Impact – Prompt Dose effects in semiconductor devices and circuits are the result of a flash x-ray (FXR) or a burst of energetic electrons
• DD Impact – Displacement Damage in semiconductor devices is caused by exposure to a large flux of protons or neutrons
• SEA Assessment Table – Single Event Anlaysis in semiconductor devices are caused by energetic cosmic ray and solar flare particles
• SEU/SET Duration, Rate and Impact – Single Event Upset and Single Event Transients
• Derating Guidelines – performance degradation as a function of dose and/or displacement levels, end-of-life performance including allowance for aging and temperature effects
• Hardness Assurance Plans – Tailored to program requirements and current Mil specifications

FMEA/FMECA – Failure Analysis and Troubleshooting

The FMECA (Failure Modes and Effects Criticality Analysis) consists of a definition of all of the possible Failure Modes of all elements of a system, and a determination of the Effects and Criticality of these failure modes. This analysis looks at the failure of each element within a device or system to determine the effect on the operations and end performance.

The goal is to eliminate any single-point failures that would cause the system to fail to meet its performance requirements. We validate all fail safe/fail operations conditions leading to a graceful degradation of operations and survivability.

The FMECA begins with a stress-based reliability (MTBF) analysis. This generates the failure rate of each of the components. Each component in the BOM is assigned a set of failure modes. These are normally defined using Mil-HDBK-338B which has a definition of the common types of failures for each type of component along with the probability (Mode Failure percentage) of each failure mode occurring.

MTBF/Reliability

Mean Time Between Failure (MTBF) analyses are performed based on parts-count and stress-based. The results are used to assess the potential component failure probabilities, and when the failures may occur during the product’s lifetime. The results are combined with a stress analysis and a FMECA analysis to identify design weaknesses and potential risks.

An MTBF analysis basically sums the failure rates of the parts in the BOM. The analysis produces a single number for the systems MTBF, failure rate, and reliability.

SPICE Modeling – Parts/Circuit Characterization and Test

Bastion has developed hundreds of SPICE models for discrete semiconductors, RF devices, power electronics, magnetic cores, linear regulators and dozens of other types of devices.

Thermal/Structural Engineering

Bastion provides both electro-mechanical design and thermal/structural analysis of electronic hardware components and electronics packaging. Bastion has extensive capabilities in thermal and structural design and analysis software such as Thermal Synthesizer System (TSS), ANSYS, COSMOS, Thermal Analyzer System (TAS), and ANSYS, and SolidWorks.

Bastion is highly proficient in determining component temperatures for a variety of environments and assessing random vibration fatigue life.

Customer Base

Bastion Technologies currently supports the following government and industry partners in the areas of electrical design, reliability analysis, and EEE components engineering:

• NASA/Ames Research Center
• NASA/Glenn Research Center
• NASA/Jet Propulsion Laboratory
• MASA/Marshall Space Flight Center
• Lockheed Martin
• Northrop Grumman
• Aitech
• Mercury Systems