Performing Sneak Circuit Analysis on critical products for more than 20 years

Sneak Circuit Analysis (SCA) is an established means for finding latent design flaws (rather than component failures) that cause behavior problems in control circuits and systems. These design flaws cause anomalies such as train doors that open while the train is in motion or the un-commanded launch of a missile. Sneak conditions are classified into four basic types:

  • Sneak Paths – unintended electrical (current) paths within a circuit and its external interfaces
  • Sneak Timing – unexpected interruption or enabling of a signal due to switch circuit timing problems which may cause or prevent the activation or inhibition of a function at an unexpected time
  • Sneak Indications – undesired activation or deactivation of an indicator which may cause an ambiguous or false display of system operating conditions
  • Sneak Labels – incorrect or ambiguous labeling of a switch which may cause operator error through inappropriate control activation

In-house automated analysis tool

Engineering analysts have performed Sneak Circuit Analysis on critical systems for decades, but without automation the analysis has been tedious, error-prone and labor-intensive. As a result, the usefulness of the analysis has generally been limited to projects with large budgets and extended schedules. Our Automated Sneak Circuit Analysis tool provides a complete and fully accurate assessment of sneak behavior while minimizing possibilities of human errors. Its automated approach substantially lowers cost and analysis time while greatly improving accuracy and thoroughness.

With this tool, Sneak Circuit Analysis is now feasible for all critical designs as its cost is on par with the commonly applied Failure Modes, Effects, and Criticality Analysis (FMECA).

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FPGA Sneak Circuit Analysis

Along with our history of designing safety-critical and mission-critical FPGAs, we have extensive experience analyzing them. Keeping these experiences in mind, we developed an automated FPGA Sneak Circuit Analysis tool that substantially lowers cost and analysis time while greatly improving accuracy and thoroughness, efficiently identify unexpected behavior in your FPGA designs and its control circuits. Our approach is based on the document “The Application of Sneak Analysis to Safety Critical FPGAs” from the University of York. 

FPGA Sneak Circuit Analysis (SCA) determines the possibility of unexpected behavior in electrical or electronic control circuits when operating as designed, without failures. Undesired behavior appears as accidental circuit outputs that result from unintended input combinations or sequences.

Finding Hidden Hazards in FPGA-Based Control Circuits

While SCA has been applied to many types of control circuits over the years, a more recent application is the analysis of FPGAs and related firmware devices. Such devices operate quite differently than circuits with interconnected discrete components. Sneak Circuit Analysis is applied to determine FPGA output consequences caused by unexpected sets of inputs. However, FPGAs by nature require different and more sophisticated analyses methods.

Collect Process and Evaluate System Design Information

  • Schematic, installation drawings
  • System description, parts lists
  • System level hazards


Perform Analysis

  • Hazard severity prioritization
  • Candidate list, partitioning
  • Topological pattern identification, clue application
  • Identification and documentation of Sneak conditions
  • Recommended corrective actions

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Solutions to Sneak Circuit Analysis of Very Large Equipment/Systems Designs

What’s Inside: Performing a Sneak Circuit Analysis on a large or complex system has traditionally been a labor-intensive task. Because of the sheer cost of the huge amount of time that it typically takes to complete this kind of analysis, this process is often overlooked, or de-prioritized in order to meet schedule, and budgetary constraints.