RoHS compliance in safety and reliability critical electronics

In some safety- and reliability-critical applications, electronic products are subjected to harsh operating conditions for a lifetime ranging over ten years. For instance, the Emerson DVC6215 remote mount sensor has operating requirements from − 52 °C to 120 °C along with the ability to withstand high rates of temperature fluctuations during manufacture and vibration up to 50G's during use. Since safety- and reliability-critical products are designed for use in industries with specialized operating conditions, there is no standardized set of operating conditions for these products. As a result, such products were exempt from the EU's Restriction of Hazardous Substances (RoHS) directive passed in 2006. However, specific deadlines have been set for exempt industries in the 2011 recast version of the RoHS directive. This paper provides a systematic lead-free transition plan in safety- and reliability-critical products. Existing lead-free solder options for harsh environmental operating conditions are evaluated along with the pros and cons in RoHS compliance.