AOS Semiconductor Product Reliability Report AO4812/AO4812L, rev B Plastic Encapsulated Device ALPHA & OMEGA Semiconductor, Inc 495 Mercury Drive Sunnyvale, CA 94085 U.S. Tel: (408) 830-9742 www.aosmd.com Feb 16, 2006 1 This AOS product reliability report summarizes the qualification result for AO4812. 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 AO4812 passes AOS quality and reliability requirements. The released product will be categorized by the process family and be monitored on a quarterly basis for continuously improving the product quality. Table of Contents: I. II. III. IV. V. Product Description Package and Die information Environmental Stress Test Summary and Result Reliability Evaluation Quality Assurance Information I. Product Description: The AO4812 uses advanced trench technology to provide excellent RDS(ON) and low gate charge. The two MOSFETs make a compact and efficient switch and synchronous rectifier combination for use in buck converters. AO4812 is Pb-free (meets ROHS & Sony 259 specifications). AO4812L is a Green Product ordering option. AO4812 and AO4812L are electrically identical. Absolute Maximum Ratings TA=25°C unless otherwise noted Parameter Symbol Maximum Units Drain-Source Voltage VDS 30 V Gate-Source Voltage VGS ±20 V Continuous Drain Current TA=25°C TA=70°C Pulsed Drain Current TA=25°C Power Dissipation TA=70°C Junction and Storage Temperature Range Thermal Characteristics Parameter Maximum Junction-toAmbient Maximum Junction-toAmbient Maximum Junction-to-Lead 6.9 ID 5.8 IDM 30 2 PD W 1.44 TJ, TSTG -55 to 150 Symbol t ≤ 10s SteadyState SteadyState A RθJA RθJL °C Typ Max Units 48 62.5 °C/W 74 110 °C/W 35 40 °C/W 2 II. Die / Package Information: Process AO4812 AO4812L (Green Compound) Standard sub-micron Standard sub-micron low voltage N channel process low voltage N channel process Package Type Lead Frame Die Attach Bond wire Mold Material Filler % (Spherical/Flake) Flammability Rating Backside Metallization Moisture Level SOIC-8 Copper with Solder Plate Ag epoxy 2 mils Au wire Epoxy resin with silica filler 90/10 UL-94 V-0 Ti / Ni / Ag Up to Level 1 * SOIC-8 Copper with Solder Plate Ag epoxy 2 mils Au wire Epoxy resin with silica filler 100/0 UL-94 V-0 Ti / Ni / Ag Up to Level 1* Note * based on info provided by assembler and mold compound supplier III. Result of Reliability Stress for AO4812 (Standard) & AO4812L (Green) Test Item Test Condition Time Point Solder Reflow Precondition Standard: 1hr PCT+3 cycle reflow@260°c Green: 168hr 85°c /85%RH +3 cycle reflow@260°c Temp = 150°c , Vgs=100% of Vgsmax 0hr HTGB HTRB HAST Pressure Pot Temperature Cycle Temp = 150°c , Vds=80% of Vdsmax 130 +/- 2°c , 85%RH, 33.3 psi, Vgs = 80% of Vgs max 121°c , 15+/-1 PSIG, RH=100% -65°c to 150°c , air to air, 0.5hr per cycle 168 / 500 hrs 1000 hrs 168 / 500 hrs 1000 hrs 100 hrs 96 hrs 250 / 500 cycles Number of Failures 0 Lot Attribution Total Sample size Standard: 49 lots Green: 16 lots 9625 pcs 17 lots 1394 pcs (note A*) 77+5 pcs / lot 17 lots 1394 pcs (note A*) 77+5 pcs / lot Standard: 33 lots Green: 13 lots 2530 pcs 0 50+5 pcs / lot 3575 pcs 0 50+5 pcs / lot 3520 pcs 0 (note B**) Standard: 49 lots Green: 16 lots (note B**) Standard: 49 lots Green: 15 lots (note B**) 0 0 50+5 pcs / lot 3 III. Result of Reliability Stress for AO4812 (Standard) & AO4812L (Green) Continues DPA Internal Vision Cross-section X-ray CSAM NA 5 5 5 5 5 5 0 NA 5 5 0 Bond Integrity Room Temp 150°c bake 150°c bake 0hr 250hr 500hr 40 40 40 40 wires 40 wires 40 wires 0 Solderability 230°c 5 sec 15 15 leads 0 Die shear 150°c 0hr 10 10 0 Note A: The HTGB and HTRB reliability data presents total of available AO4812 and AO4812L burn-in data up to the published date. Note B: The pressure pot, temperature cycle and HAST reliability data for AO4812 and AO4812L comes from the AOS generic package qualification data. IV. Reliability Evaluation FIT rate (per billion): 1.2 MTTF = 95129years In general, 500 hrs of HTGB, 150 deg C accelerated stress testing is equivalent to 15 years of lifetime at 55deg C operating conditions (by applying the Arrhenius equation with an activation energy of 0.7eV and 60% of upper confidence level on the failure rate calculation). AOS reliability group also routinely monitors the product reliability up to 1000 hr at and performs the necessary failure analysis on the units failed for reliability test(s). The presentation of FIT rate for the individual product reliability is restricted by the actual burn-in sample size of the selected product (AO4812). Failure Rate Determination is based on JEDEC Standard JESD 85. FIT means one failure per billion hours. Failure Rate = Chi2 x 109 / [2 (N) (H) (Af)] = 1.83 x 109 / [ 2 (17×164) (1000) (258) ] = 1.2 MTTF = 109 / FIT = 8.33 x 108hrs = 95129 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 – 1/Tj s )] Acceleration Factor ratio list: Af 55 deg C 70 deg C 85 deg C 100 deg C 115 deg C 130 deg C 150 deg C 258 87 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 = Boltzmann’s constant, 8.617164 X 10-5eV / K 4 V. Quality Assurance Information Acceptable Quality Level for outgoing inspection: 0.1% for electrical and visual. Guaranteed Outgoing Defect Rate: < 25 ppm Quality Sample Plan: conform to Mil-Std-105D 5