agilent 5082-7300, -7302, and -7340 hexadecimal and numeric displays reliability data sheet description the following cumulative test results have been obtained from testing performed at agilent technologies 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 but will probably be better than the performance outlined in table 1. 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 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 on the following page using an activation energy of 0.43 ev (reference mil-hdbk-217). table 1. life tests demonstrated performance stress test total units units failure rate test name conditions device hrs. tested failed [3] mtbf [1] (% /1k hours) high temperature t a = +100 c, 514,000 514 0 514,000 0.195 operating life v cc = 5.5 v numeric cycling point typical performance
www.semiconductor.agilent.com data subject to change. copyright ? 2000 agilent technologies, inc. obsoletes 5964-9632e 5968-9715e (1/00) example of failure rate calculation assume a device operating 8 hours/day, 5 days/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 50 c ambient temperature is: (0.037% / 1k hours) x (0.25) x (8760 hours/year) = 0.081% per year similarly, 90% confidence level failure rate per year at 50 c: (0.085% / 1k hours) x (0.25) x (8760 hours/year) = 0.186% per year 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 exponen tial. this particular distribution is commonly used in describing useful life failures. refer to mil-std-690b for details on this methodo logy. [3] a failure is any led which does not emit light or the displays inability to transmit information. point typical performance performance in time [1] in time [2] (60% confidence) (90% confidence) ambient junction failure rate failure rate temperature ( c) temperature ( c) mtbf [1] (%/1k hours) mtbf [2] (%/1k hours) 100 140 514,000 0.195 223,000 0.448 90 130 694,000 0.144 301,000 0.332 80 120 951,000 0.105 413,000 0.242 70 110 1,324,000 0.076 575,000 0.174 60 100 1,878,000 0.053 816,000 0.123 50 90 2,714,000 0.037 1,179,000 0.085 40 80 4,007,000 0.025 1,740,000 0.057 30 70 6,050,000 0.017 2,628,000 0.038 20 60 9,365,000 0.011 4,067,000 0.025 table 2. reliability predictions notes: [4] failures after 20 temperature cycles are considered infant failures. corrective action is required and has been implemented for all infant failures. table 3. environmental tests mil-std-883c units units test name reference test conditions tested failed temperature cycle 1010 -40 to +100 c, 15 minute dwell and 926 12 (4) 5 minute transfer, 500 cycles temperature/ C t a = +85 c, rh = 85% 515 16 humidity op life v cc = 5.0 volts solder heat resistance 2003 260 5 c, dwell time = 5 seconds, 2 times. 1916 0
|
