AOS Semiconductor Product Reliability Report AO4800B/AO4800BL, rev A Plastic Encapsulated Device ALPHA & OMEGA Semiconductor, Inc 495 Mercury Drive Sunnyvale, CA 94085 U.S. Tel: (408) 830-9742 www.aosmd.com Oct 15, 2007 1 This AOS product reliability report summarizes the qualification result for AO4800B. 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 AO4800B 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. I. Product Description Package and Die information Environmental Stress Test Summary and Result Reliability Evaluation Quality Assurance Information Product Description: The AO4800B 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. Standard Product AO4800B is Pb-free (meets ROHS & Sony 259 specifications). Absolute Maximum Ratings TA=25°C unless otherwise noted Parameter Symbol Maximum Units Drain-Source Voltage VDS 30 V Gate-Source Voltage VGS ±12 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 40 1.9 PD W 1.2 TJ, TSTG -55 to 150 Symbol T ≤ 10s SteadyState SteadyState A RθJA RθJL °C Typ Max Units 55 62.5 °C/W 90 110 °C/W 40 48 °C/W 2 II. Die / Package Information: AO4800B Process Package Type Lead Frame Die Attach Bond wire Mold Material Filler % (Spherical/Flake) Flammability Rating Backside Metallization Moisture Level AO4800BL (Green Compound) Standard sub-micron Standard sub-micron Low voltage N channel process Low voltage N channel process 8 leads SOIC 8 leads SOIC Copper with Ag spot Copper with Ag spot Ag epoxy Ag epoxy S: Cu 2mils; G: Au 1.3mils S: Cu 2mils; G: Au 1.3mils Epoxy resin with silica filler Epoxy resin with silica filler 90/10 100/0 UL-94 V-0 UL-94 V-0 Ti / Ni / Ag Ti / Ni / Ag Up to Level 1 * Up to Level 1* Note * based on info provided by assembler and mold compound supplier III. Result of Reliability Stress for AO4800B (Standard) & AO4800BL (Green) Number of Failures Test Item Test Condition Time Point Lot Attribution Total Sample size 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 Standard: 7 lots 770 pcs 0 168 / 500 hrs 1 lot 82 pcs 0 1000 hrs (Note A*) 168 / 500 hrs 1 lot 1000 hrs (Note A*) 100 hrs Standard: 3 lots 165 pcs 0 96 hrs (Note B**) Standard: 4 lots 50+5 pcs / lot 220 pcs 0 50+5 pcs / lot 385 pcs 0 HTGB HTRB HAST Pressure Pot Temp = 150°c , Vds=80% of Vdsmax 130 +/- 2°c , 85%RH, 33.3 psi, Vgs = 80% of Vgs max 121°c , 29.7psi, 100%RH (Note B**) Temperature Cycle -65°c to 150°c , air to air 250 / 500 cycles Standard: 7 lots (Note B**) 77+5 pcs / lot 82 pcs 0 77+5 pcs / lot 50+5 pcs / lot 3 III. Result of Reliability Stress for AO4800B (Standard) & AO4800BL (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 245°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 AO4800B and AO4800BL burn-in data up to the published date. Note B: The pressure pot, temperature cycle and HAST reliability data for AO4800B and AO4800BL comes from the AOS generic package qualification data. IV. Reliability Evaluation FIT rate (per billion):128 MTTF = 891years In general, 500 hrs of HTGB, 150 deg C accelerated stress testing is equivalent to 15 years of lifetime at 55 deg 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 (AO4800B). 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 (164) (168) (258)] = 128 MTTF = 109 / FIT = 7.81 x 106hrs =891years 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