Switch-Mode Power Supplies: Understanding and applying mean-time-between-failures correctly.
Will a power supply with an MTBF of one million hours last 114 years? (No)
Is the power supply with the highest MTBF always the most reliable in operation? (No)
Are MTBF calculations then without any value? (Definitely not!)
MTBF (Mean Time Between Failure) calculations are unfortunately not always properly understood. In order to shed light on this often misunderstood topic, this guide shows the derivation and implementation of MTBF figures using examples and explains the differences and similarities between the various MTBF protocols (MIL-HDBK, Telcordia SR-332, Siemens SN 29500, IEC 61709).
When used correctly, MTBF calculations are a very useful tool and allow manufacturers to develop highly reliable power supplies. At the same time, users can estimate the expected lifetime of their systems and make necessary maintenance or replacement plans.