How to read datasheets
Which correctly describes the concept of component "derating"?
- ARatings already include margin, so using parts right up to their ratings is the most economical
- BRun parts briefly under conditions harsher than their ratings and use only those that pass
- CTo improve reliability, use parts with margin on voltage, temperature and so on rather than right up to their ratings
Show answer and explanation
Answer: C. To improve reliability, use parts with margin on voltage, temperature and so on rather than right up to their ratings
Derating is the design practice of using parts with margin relative to their ratings. Companies and industries set guidelines such as keeping voltage at or below 70–80% of the rating and junction temperature at or below 125 °C against a 150 °C maximum rating. Component failure rates rise with greater temperature and voltage stress, so more margin means longer life. Running parts under conditions harsher than their ratings to weed out early failures is screening (burn-in), a technique separate from derating.