EURO QUARTZ PRODUCT SPECIFICATION MTTF CALCULATION FOR SEAM SEALED CRYSTALS Based on operation +25°C SAMPLE TYPES: NUMBER OF PARTS TESTED: NUMBER OF FAILURES: ACCELERATED TEMPERATURE: TEST HOURS: MQ (7 x 5mm) MF (6 x 3.5mm) MJ (5 x 3.2mm) X42 (4 x 2.5mm) MT (3.2 x 2.5mm) X32 (3.2 x 2.5mm) X22 (2.5 x 2.0mm) 3170 pieces 0 pieces +125°C 1000 hours ARRHENIUS MODEL Symbol Description Formula / Value (EaK ).(T1 T1 ) AF Acceleration Factor AF = e Ea Activation Energy 0.437 eV K Boltzmann's Constant 8.617 x 10-5 eV/K T1 Operating Temperature (K) +25°X = 298°K T2 Accelerated Temperature (K) +125°C = 398°K Tt Total Device Hours = (number of devices) x (test hours at T2) X2 Chi-squared For zero failure 1.833 at 60% confidence level 4.605 at 90% confidence level Mean Time to Failure =(2 x AF x Tt) / X2 Failures in Time = 109 / MTTF MTTF FIT 1 2 According to above formulae, MTTF and FIT are calculated as follows: Confidence Level MTTF (Hours) FIT 60% 2.48 x 108 4.02 90% 9.89 x 107 10.11 EUROQUARTZ LIMITED Blacknell Lane CREWKERNE Somerset UK TA18 7HE Tel: +44 (0)1460 230000 Fax: +44 (0)1460 230001 [email protected] www.euroquartz.co.uk