AOS Semiconductor Product Reliability Report AO4948/AO4948L, rev A Plastic Encapsulated Device ALPHA & OMEGA Semiconductor, Inc 495 Mercury Drive Sunnyvale, CA 94085 U.S. Tel: (408) 830-9742 www.aosmd.com 1 This AOS product reliability report summarizes the qualification result for AO4948. 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 AO4948 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 AO4948/L 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 DC-DC converters. A monolithically integrated Schottky diode in parallel with the synchronous MOSFET to boost efficiency further. AO4948 and AO4948L are electrically identical. -RoHS Compliant -AO4948L is Halogen Free 2 II. Die / Package Information: Process Package Type Lead Frame Die Attach Bond wire Mold Material Flammability Rating Backside Metallization Moisture Level AO4948 Standard sub-micron Low voltage N channel process 8 leads SOIC Cu, D/pad Ag spot Ag epoxy S: Cu 2mils; G: Au 1.3mils Epoxy resin with silica filler UL-94 V-0 Ti / Ni / Ag Up to Level 1 * AO4948L (Green Compound) Standard sub-micron Low voltage N channel process 8 leads SOIC Cu, D/pad Ag spot Ag epoxy S: Cu 2mils; G: Au 1.3mils Epoxy resin with silica filler 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 AO4948 (Standard) & AO4948L (Green) 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 - Standard: 83 lots Green: 29 lots 17380 pcs 0 77 pcs 0 HTGB 168hrs 500 hrs 1000 hrs 1 lot (Note A*) Number of Failures 77 pcs / lot HTRB Temp = 150°c , Vds=80% of Vdsmax 168hrs 500 hrs 1000 hrs 1 lot HAST 130 +/- 2°c , 85%RH, 33.3 psi, Vgs = 80% of Vgs max 100 hrs Standard: 81 lots Green: 16 lots 5335 pcs 0 Pressure Pot 121°c , 29.7psi, RH=100% 96 hrs (Note B**) Standard: 83 lots Green: 20 lots 55 pcs / lot 5665 pcs 0 Temperature Cycle -65°c to 150°c , air to air 250 / 500 cycles (Note B**) Standard: 87 lots Green: 29 lots 55 pcs / lot 6380 pcs 0 (Note B**) 55 pcs / lot (Note A*) 77 pcs 0 77 pcs / lot 3 III. Result of Reliability Stress for AO4948 (Standard) & AO4948L (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 Note A: The HTGB and HTRB reliability data presents total of available AO4948 and AO4948L burn-in data up to the published date. Note B: The pressure pot, temperature cycle and HAST reliability data for AO4948 and AO4948L comes from the AOS generic package qualification data. IV. Reliability Evaluation FIT rate (per billion): 137 MTTF = 833 years The presentation of FIT rate for the individual product reliability is restricted by the actual burn-in sample size of the selected product (AO4948). 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 / [2x2x77x258] = 137 9 6 MTTF = 10 / FIT = 7.30 x 10 hrs = 833 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