What’s the Hype with High-Reliability (Hi-Rel)

It is common to see high reliability (Hi-Rel) labelled electronic components and devices in virtually every automotive, industrial, avionics, military, and space application. Obviously, these applications have widely different standards and expectations for reliability. For example, an automotive device may have an expected failure rate over 5 years that is orders of magnitude less than a satellite device may be specified for over 15 years. This leads many technical professionals wondering what exactly does Hi-Rel mean, or assuming it just mean more reliable than a cheaper part.

High reliability simply implies that a component may have a consistent performance over a certain lifetime, a statistical failure rate below a certain figure, or have passed one of the many high-reliability standards qualifications. Depending on the qualifications met, this could mean that only one part is several million is predicted to fail over a several year lifetime, or that a part is rated to operate nominally even in extreme environmental circumstances.

Caption: Electronic components, amongst others, can be described statistically using a bathtub curve, where components can be assumed to operate at a low failure rate during a nominal life cycle.

In fact, Hi-Rel has many meanings, and it does depend on the application, industry, and the specific technical features that a component and a device supports. For example, a Hi-Rel coaxial cable or connector will be subject to different commercial, automotive/aerospace, US military, or European Standards requirements depending on its intended use and what systems it may be integrated with. Though not always the case, a part labelled Hi-Rel will sometimes also have listed what standards the part is rated too. However, anyone procuring any parts should be mindful that depending on the types of testing done, a product line many be labeled Hi-Rel even without a specific part having been tested against the quality standards.

Many standards also pose guidelines and have wide ranges of acceptable conditions, so comparing between components labelled Hi-Rel can also be challenging due to ambiguity. This is where leveraging a supplier that is trusted with technical experts on hand to guide a buyer through the selection process can be key. With RF/microwave components being integrated into critical systems for the latest medical, aerospace, high-throughput satellites, autonomous vehicles etc., it is even more paramount to ensure reliability standards are met for each component and assembled system.

The list below references some commonly used high reliability standards

High Reliability Electronics Standards

IEC/TR 62380 Ed. 1.0 en:2004

ASTM F1448-16

ISO/IEC 15149:2011

IPC J-STD-001F+Amd1-2016

Automotive and Aerospace Industry High Reliability Standards

SAE AS 5553B-2016 (SAE AS5553B-2016)

SAE AS 5643/1-2004 (SAE AS5643/1-2004)

SAE AS 5706-2007 (SAE AS5706-2007)

SAE AS 94900-2007 (SAE AS94900-2007)

SAE J 1211-2012 (SAE J1211-2012)

SAE J 1879-2014 (SAE J1879-2014)

SAE J 1938-2015 (SAE J1938-2015)

United States MIL-STDs

MIL-C 38999

MIL-C 83723

MIL-C 5015

MIL-C 26482

MIL-C 26500

MIL-C 83513

MIL-C 81511

MIL-STD-1686C

MIL-STD-188-124B NOT 3

MIL-STD-196E

MIL-STD-690D

MIL-PRF-55585G

MIL-HDBK-217F(2)

MIL-HDBK-251

MIL-HDBK-263B

MIL-HDBK-338B

MIL-HDBK-344A

MIL-HDBK-781A

European Connector Specifications

EN 2997

ESC 10

ESC 11

ESC 15