Reliable LEDs for Automotive Grade Optocouplers

One of the key enablers for optocouplers to handle automotive grade 1 applications is the use of very high performance LEDs. The LED light output dropping by less than 0.2%/°C, aids in achieving high temperature specifications and the improvements in LED design and fabrication. Coupled with package design, this has demonstrated very reliable performance. Based on the mission profiles of some automobiles 15 years old, this translated to about 2000 hrs under highly accelerated continuous operating life stress conditions. With current transfer ratio drop of less than 10% after 5000 hrs of stress, system designers can accommodate such variations to cover more than 35 years of the automobiles life.