aos semiconductor product reliability report AON6978 , rev a plastic encapsulated device alpha & omega semiconductor, inc www.aosmd.com
this aos product reliability report summarizes the qualification result for AON6978 . accelerated environmental tests are performed on a specific sample size, and then followed by electrical test at end point. review of final electrical test result confirms that AON6978 passes aos quality and reliability requirements. table of contents: i. product description ii. package and die information iii. environmental stress test summary and result iv. reliability evaluation i. product description: ? latest trench power alphamos ( mos lv) technology ? integrated schottky diode (srfet) on low - side ? very low r ds(on) at 4.5 v v gs ? low gate charge ? high current capability application ? dc/dc converters in computing, servers, and pol ? isolated dc/dc converters in telecom and industrial - rohs compliant - halogen - free detailed information refers to datasheet. ii. die / package information: AON6978 process standard sub - micron l ow voltage n channel package type dfn 5 x 6 b lead frame bare c u die attach ag epoxy bonding cu & au wire mold material epoxy resin with silica filler msl (moisture sensitive level) level 1 based on j - std - 020 note * based on info rmation provided by assembler and mold compound supplier
iii. result of reliability stress for AON6978 test item test condition time point lot attribution total sample size number of failures standard msl precondition 168hr 85 c /85 %rh +3 cycle reflow@260c - 12 lots 2310 pcs 0 jesd22 - a113 htgb temp = 150 ? c , vgs=100% of vgsmax 168 hrs 500 hrs 1000 hrs 1 lot 4 lots 2 lots 539 pcs 77pcs / lot 0 jesd22 - a 108 htrb temp = 150 ? c , vds=80% of vdsmax 168 hrs 500 hrs 1000 hrs 1 lot 4 lots 2 lots 539 pcs 77pcs / lot 0 jesd22 - a108 hast 130 ? c , 85% rh , 33.3 psi, v d s = 8 0 % of v d s max 96 hrs 9 lots (note a*) 693 pcs 77 pcs / lot 0 jesd22 - a110 pressure pot 121 ? c , 29.7psi , rh=100% 96 hrs 9 lots (note a*) 693 pcs 77 pcs / lot 0 jesd22 - a102 temperature cycle - 65 ? c to 150 ? c , air to air 250 / 500 cycles 12 lots (note a*) 924 pcs 77 pcs / lot 0 jesd22 - a104 note a: the reliability data presents total of available generic data up to the published date. iv. reliability evaluation fit rate (per billion): 5 .49 mt t f = 20784 years the presentation of fit rate for the individual product reliability is restricted by the actual burn - in sample size of the selected product ( AON6978 ). failure rate determination is based on jedec standard jesd 85. fit means one failure per billion hours. failure rate = chi 2 x 10 9 / [ 2 (n) (h) (af) ] = 1.83 x 10 9 / [ 2 x ( 2 x77x 168 + 8x77x500 +4 x77x 1000) x 2 59 ] = 5 .49 mt t f = 10 9 / fit = 1.82 x 10 8 hrs = 20784 years chi2 = chi squared distribution, determined by the number of failures and confidence interval n = total number of units from htrb and htgb tests h = duration of htrb/htgb testing af = acceleration factor from test to use conditions (ea = 0.7ev and tuse = 55 c ) acceleration factor [af ] = exp [ea / k ( 1/tj u C 1/tj s )] acceleration factor ratio list: 55 deg c 70 deg c 85 deg c 100 deg c 115 deg c 130 deg c 150 deg c af 2 59 8 8 32 13 5.64 2.59 1 tj s = stressed junction temperature in degree (kelvin), k = c+273.16 tj u = the use junction temperature in degree (kelvin), k = c+273.16 k = boltz m an n s constant, 8.617164 x 10 - 5 e v / k
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