Complex Electronics
Classification
The first step in tailoring any process or set of activities is to understand the criteria used to decide what activities are necessary, and which are not. The main criteria for complex electronics are criticality and complexity. Critical devices, such as those used in safety-related components or those that implement mission-critical functions, will require the most assurance activities to be applied. Similarly, highly complex or risky devices also require enhanced assurance activities, to gain sufficient confidence in the final product. On the other hand, non-critical and low-complexity devices will require only the minimum set of assurance activities.
The criteria used to classify the complex electronics are defined below. If any of the definitions (each bullet) is met, then the complex electronics is given that classification. Start at the top – assess if the CE is high assurance. If not, see if it meets the moderate criteria. If the device is neither High nor Moderate, it is classified as Low.
Assurance Classification |
Criteria |
High |
- The complex electronics executes safety-critical functions
- The complex electronics executes mission-critical functions and is a single point of failure
- The design is expected to be highly complex
- The design is expected to have significant risk due to one or more of these factors:
- Unstable requirements
- Technical concerns with the chosen technology, such as power consumption, design size for the chip, timing, packaging, or operating frequency
- Highly innovative and untried design approach
- Highly aggressive schedule
- Inexperience of the design team
|
Moderate |
- The complex electronics executes mission-critical functions but there is redundancy in the system
- The design is expected to be moderately complex
- The design is expected to have moderate risk due to one or more of these factors:
- Some requirements undefined or unstable
- Somewhat innovative and untried design approach
- Aggressive schedule
- Design team contains some inexperienced members
|
Low |
The complex electronics is classified as Low if it does not fall into either of the above categories |
The classification above is meant to be a guideline for tailoring the assurance process. The system within which the complex electronics operates, and the functions it performs, may modify the classification higher or lower. The classification chosen for a device should be agreed to by the project manager, project engineer, and assurance engineer.
Below are two examples where the classification is modified by other parameters:
- Distributed systems. Systems with one or more complex devices (or a complex electronic device and software) that jointly control a system or coordinate among themselves require assurance beyond the devices themselves. The interfaces and timing of communication are important to consider. Regardless of the complexity of the complex electronic design, the assurance level should be high because of the external factors.
- Complex electronics as part of an off-the-shelf circuit board. Sometimes an FPGA or CPLD will be part of an off-the-shelf board. Since the design of the device is probably not available, you cannot perform any analysis or in-depth verification of the device. If the device is not used for safety or mission critical purposes, it can probably be considered a low assurance.
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