subminiature lamps reliability data description the following cumulative test results have been obtained from testing performed at hp optoelec- tronics division in accordance with the latest revision of mil- std-883. hewlett-packard tests parts at the absolute maximum rated condi- tions recommended for the device. the actual performance you obtain from hp parts depends on the electrical and environmen- tal characteristics of your applica- point typical performance stress test total device units total failure rate colors conditions hours tested failed mtbf (% /1 k hours) standard red t a = 55 c, i f = 50 ma 2,658,000 2,210 0 2,658,000 0.038% her, green, t a = 55 c, i f = 30 ma 10,423,000 7,063 0 10,423,000 0.010 % emerald green, orange, yellow, as and ts algaas yellow t a = 55 c, i f = 20 ma 3,218,000 2,098 0 3,218,000 0.031 % table 1. life tests demonstrated performance failure rate prediction the failure rate of semiconductor devices is determined by the junction temperature of the device. the relationship between ambient temperature and actual junction temperature is given by the following: t j ( c) = t a ( c) + q ja p avg where t a = ambient temperature in c q ja = thermal resistance of junction-to-ambient in c/watt hlmp-pxxx, qxxx, 6xxx, 70xx tion but will probably be better than the performance outlined in table 1. p avg = average power dissipated in watts the estimated mtbf and failure rate at temperatures lower than the actual stress temperature can be determined by using an arrhenius model for temperature acceleration. results of such calculations are shown in the table below using an activation energy of 0.43 ev (reference mil-hdbk-217).
2 example of failure rate calculation: assume a device operating 8 hours /day, 5 days a week. the utilization factor, given 168 hours /week is: (8 hours/day) x (5 days/week) ? (168 hours/week) = 0.25 the point failure rate per year (8760 hours) at 55 c ambient temperature is: (0.010% /1k hours) x 0.25 x (8760 hours/year) = 0.022% per year similarly, 90% confidence level failure rate per year at 55 c: (0.022% /1k hours) x 0.25 x (8760 hours/year) = 0.048% per year table 2. point typical performance in time [2] performance [1] in time (90%confidence) ambient temp. junction temp. failure rate failure rate i f ( c) ( c) mtbf [1] (%/1k hours) mtbf [2] (%/1k hours) 30 85 105 3,340,000 0.030 % 1,451,000 0.069 % 75 95 4,782,000 0.021 % 2,077,000 0.048 % 65 85 6,983,000 0.014 % 3,033,000 0.033 % 55 75 10,423,000 0.010 % 4,527,000 0.022 % 45 65 15,930,000 0.006 % 6,919,000 0.014 % 35 55 24,986,000 0.004 % 10,852,000 0.009 % 25 45 40,313,000 0.002 % 17,509,000 0.006 % notes: 1. the point typical mtbf (which represents 60% confidence level) is the total device hours divided by the number of failures. in the case of zero failures, one failure is assumed for this calculation. 2. the 90% confidence mtbf represents the minimum level of reliability performance which is expected from 90% of all samples. this confidence interval is based on the statistics of the distribution of failures. the assumed distribution of failures is exponential. this particular distribution is commonly used in describing useful life failures. refer to mil-std-690b for details on this methodology. 3. a failure is any led which does not emit light.
3 table 3. environmental tests units units test name reference test conditions tested failed infra-red solder hp application note 1028 re-flow at 235 c peak, above 1,912 0 re-flow 185 c for 90 sec. max. solder heat resistance mil-std-883 method 2003 sn 60, pb 40, solder at 260 c for 3,596 0 5 seconds temperature cycle mil-std-883 method 1010 -55 c to 100 c, 15 min. dwell, 5 min. transfer 20 cycles 8308 0 500 cycles 8308 0 humidity life jis c 7021 method b-11 85 c, 85 % rh, 10 ma, 1000 hours 1,680 0 condition c humidity life jis c 7021 method b-11 85 c, 85 % rh, 30 ma, 1000 hours 112 0 condition c humidity life jis c 7021 method b-11 85 c, 85 % rh, 20 ma, 1000 hours 112 0 condition c power temperature automotive specs. -40 c to 85 c, 15 min. dwell, 5 min. cycle transfer, 20 ma, 5 mins. on/off 20 cycles 336 0 500 cycles 336 0 corrosion mil-std-883 method 1009 35 c, 24 hours 38 0 salt atmosphere table 4. mechanical tests units units test name reference test conditions tested failed mechanical shock mil-std-883 method 2002 3 shocks each x1, x2, y1, y2, z1, z2 60 0 axis, 3000 g, 0.3msec. pulse vibration variable mil-std-883 method 2007 4 cycles, 4 minute each x1, y1, y2 60 0 frequency axis at 20 g minimum, 20 to 2000 hz vibration fatigue mil-std-883 method 2005 32 8 hours each x, y, z axis at 20 g 60 0 minimum, 96 hours total
www.hp.com/go/led for technical assistance or the location of your nearest hewlett-packard sales office, distributor or representative call: americas/canada: 1-800-235-0312 or 408-654-8675 far east/australasia: call your local hp sales office. japan: (81 3) 3335-8152 europe: call your local hp sales office. data subject to change. copyright ? 1999 hewlett-packard co. obsoletes 5962-9790e 5968-7069e (9/99)
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