seven segment displays ultra mini, 0.3 mini, 0.3 inch reliability data description the following cumulative test results have been obtained from testing performed at agilent optoelectronics division in accordance with the latest revision of mil- std-883. agilent tests parts at the absolute maximum rated conditions recommended for the device. the actual performance you obtain from agilent parts depends on the electrical and environmental characteristics of your application point typical performance stress test total device units total failure rate colors conditions hours tested failed mtbf (%/1 k hours) yellow t a = 55 c, i f = 20 ma 10,500 21 0 10,500 0.95 % std red t a = 55 c, i f = 25 ma 147,000 21 0 147,000 0.68 % green t a = 55 c, i f = 30 ma 399,000 63 0 399,000 0.25 % her t a = 55 c, i f = 30 ma 399,000 63 0 399,000 0.25 % 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 hdsp-uxxx, HDSP-AXXX, hdsp-3xxx, hdsp-4xxx, hdsp-7xxx 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).
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 25 c ambient temperature is: (0.027% /1k hours) x 0.25 x (8760 hours/year) = 0.059% per year similarly, 90% confidence level failure rate per year at 25 c: (0.104% /1k hours) x 0.25 x (8760 hours/year) = 0.228% 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 85 115 357,000 0.280% 92,000 1.089% 75 105 502,000 0.199% 129,000 0.775% 65 95 718,000 0.139% 185,000 0.542% 55 85 1,049,000 0.095% 270,000 0.371% 45 75 1,566,000 0.064% 403,000 0.248% 35 65 2,393,000 0.042% 615,000 0.163% 25 55 3,753,000 0.027% 965,000 0.104% 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. table 3. environmental tests units units test name reference test conditions tested failed solder heat resistance mil-std-883 method 2003 260 c, 3 seconds 10 0 temperature cycle mil-std-883 method 1010 -55 c to 100 c, 15 min. dwell, 1000 1 5 min. transfer, 20 cycles humidity storage jis c 7021 method b-11 85 c, 85% rh, 168 hours 103 0 solderability mil-std-883 method 2003 16 hours steam aging followed by 10 0 solder dip at 260 c for 5 seconds salt atmosphere mil-std-883 method 1009 35 c, 24 hours 10 0 table 4. mechanical tests units units test name reference test conditions tested failed terminal strength mil-std-883 method 2004 cond. a 1 lb. for 30 sec. 11 0 lead strength mil-std-883 method 2004 cond. b 3 x 90 degree bend, 8 oz. 11 0 vibration variable mil-std-883 method 2007 2 hours for each x, y, z axis at 22 0 frequency 20 gs, 10 to 2k hz; 20 min. sweep www.semiconductor.agilent.com data subject to change. copyright ? 1999 agilent technologies 5968-7073e (11/99)
|
