ASMT-TWBM / ASMT-TBBM / ASMT-TGBM Surface Mount LED Indicator Reliability Data Sheet Description Failure Rate Prediction The following cumulative test results have been obtained The junction temperature of the device determines the from testing performed at Avago Technologies in accor- failure rate of semiconductor devices. The relationship dance with the latest revision of MIL-STD-883 and JEDEC. between ambient temperature and actual junction tem- perature is given by the following: Avago tests parts at the absolute maximum rated con- T (C) = T (C) + P ditions recommended for the device. The actual per- J A JA AVG formance you obtain from Avago parts depends on Where the electrical and environmental characteristics of your T = ambient temperature in (C) A application but will probably be better than the perfor- = thermal resistance of junction-to ambient in C/watt mance outlined in Table 1. JA P = average power dissipated in watts AVG The estimated MTTF and failure rate at temperatures lower than the actual stress temperature can be deter- mined by using an Arrhenius model for temperature acceleration. Results of such calculations are shown in the table below using activation energy of 0.43eV (reference MIL-HDBK-217). Table 1. Life Tests Demonstrated Performance Point Typical Performance Total Device Units Units MTBF Failure Rate Colors Stress Test Conditions Hours Tested Failed (60% Confidence) (%/1K Hrs) Green T = 55C, I = 20 mA 56,000 56 0 61,100 1.64 A F Blue / Ice Blue / T = 55C, I = 18 mA 56,000 56 0 71,700 1.39 A F Cool WhiteReliability Prediction Table 2a. Green (I = 20mA) F Point Typical 1 - 5 1 - 5 Performance in Time Performance in Time (60% Confidence) (90% Confidence) Ambient Junction Failure Rate Failure Rate Temperature (C) Temperature (C) MTTF (%/1K Hours) MTTF (%/1K Hours) 100 125 38500 2.60 15300 6.54 95 125 39200 2.55 15600 6.41 90 124 40000 2.50 15900 6.29 85 123 40700 2.46 16200 6.17 80 123 41500 2.41 16500 6.06 75 122 42300 2.36 16800 5.95 70 122 43100 2.32 17200 5.81 65 121 43900 2.28 17500 5.71 60 116 51700 1.93 20600 4.85 55 111 61100 1.64 24300 4.12 50 106 72500 1.38 28900 3.46 45 101 86500 1.16 34400 2.91 40 96 103600 0.97 41200 2.43 35 91 124700 0.80 49600 2.02 30 86 151000 0.66 60100 1.66 25 81 183700 0.54 73100 1.37 Table 2b. Blue / Ice Blue / Cool White (I = 18mA) F Point Typical 1 - 5 1 - 5 Performance in Time Performance in Time (60% Confidence) (90% Confidence) Ambient Junction Failure Rate Failure Rate Temperature (C) Temperature (C) MTTF (%/1K Hours) MTTF (%/1K Hours) 100 108 63800 1.57 25400 3.94 95 108 64600 1.55 25700 3.89 90 107 65400 1.53 26000 3.85 85 107 66300 1.51 26400 3.79 80 107 67100 1.49 26700 3.75 75 106 68000 1.47 27100 3.69 70 106 68900 1.45 27400 3.65 65 106 69800 1.43 27800 3.60 60 105 70700 1.41 28200 3.55 55 105 71700 1.39 28500 3.51 50 104 72600 1.38 28900 3.46 45 99 86700 1.15 34500 2.90 40 94 104100 0.96 41400 2.42 35 89 125600 0.80 50000 2.00 30 84 152200 0.66 60600 1.65 25 79 185600 0.54 73900 1.35 Notes: 1. The 60% or 90% confidence MTTF represents the minimum level of reliability performance which is expected from 60% or 90% of all samples. The confidence level is established based on the chi-square distribution. 5 2. Failure rate (FIT) is 1/MTTF x 10 , assuming the failures are exponentially distributed 3. A failure is any LED that is open, shorted or fails to emit light. 4. Calculated from data generated at 55C biased at 20mA (Green) 18mA (Blue/Ice Blue/Cool White). 5. Junction temperature is calculated based on = 850C/W JA 2