AOS Semiconductor Product Reliability Report AO4900/AO4900L, rev A Plastic Encapsulated Device ALPHA & OMEGA Semiconductor, Inc 495 Mercury Drive Sunnyvale, CA 94085 U.S. Tel: (408) 830-9742 www.aosmd.com Dec 28, 2004 1 This AOS product reliability report summarizes the qualification result for AO4900. 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 AO4900passes 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 AO4900 uses advanced trench technology to provide excellent R DS (ON) and low gate charge. The two MOSFETs make a compact and efficient switch and synchronous rectifier combination for use in DCDC converters. A Schottky diode is co-packaged in parallel with the synchronous MOSFET to boost efficiency further. AO4900L (Green Product) is offered in a lead-free package. Absolute Maximum Ratings T A=25°C unless otherwise noted Parameter Symbol Drain-Source Voltage VDS 30 V Gate-Source Voltage VGS ±12 V ID 6.9 Continuous Drain Current TA=25°C A TA=70°C B IDM Pulsed Forward Current B IFM TA=25°C A TA=70°C Junction and Storage Temperature Range Thermal Characteristics MOSFET Maximum Junctiont = 10s to-Ambient Maximum JunctionSteadyto-Ambient State Maximum JunctionSteadyto-Lead State Schottky Units 5.8 Pulsed Drain Current Schottky reverse voltage Continuous TA=25°C Forward Current A TA=70°C Power Dissipation MOSFET A 40 VKA 30 V 3 IF 2 A 40 PD TJ , TSTG Symbol RθJA RθJL 2 2 1.44 1.44 -55 to 150 -55 to 150 Typ Max 48 62.5 74 110 35 40 W °C Units °C/W 2 Thermal Characteristics Schottky Maximum JunctionT = 10s to-Ambient Maximum JunctionSteadyto-Ambient State Maximum JunctionSteadyto-Lead State Symbol RθJA Typ Max 47.5 62.5 71 110 32 40 RθJL Units °C/W II. Die / Package Information: Process AO4900 AO4900L (Green Compound) Standard sub-micron Standard sub-micron low voltage N channel process low voltage N channel process Package Type Lead Frame Die Attach Bondwire Mold Material Filler % (Spherical/Flake) Flammability Rating Backside Metallization Moisture Level 8 lead SOIC Copper with Solder Plate Silver epoxy 2 mils Au wire Epoxy resin with silica filler 50/50 UL-94 V-0 Ti / Ni / Ag Up to Level 1 * 8 lead SOIC Copper with Solder Plate Silver 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 AO4900 (Standard) & AO4900L (Green) Test Item Test Condition Time Point Lot Attribution Total Sample size Number of Failures Solder Reflow Precondition Normal: 1hr PCT+3 cycle IR reflow@240 ° c (260° c for Green) 0hr Normal: 2 lots Green: 1 lot 495 pcs 0 HTGB Temp = 150 C, Vgs=100% of Vgsmax 168 / 500 hrs Normal: 2 lots Green: 1 lot 246 pcs 0 1000 hrs (Note A*) 168 / 500 hrs Normal: 2 lots Green: 1 lot 1000 hrs (Note A*) 77+5 pcs / lot HTRB Temp = 150 C, Vds=80% of Vdsmax 246 pcs 0 77+5 pcs / lot HAST Pressure Pot 130 +/- 2 C, 85%, 33.3 psi, Vgs = 80% of Vgs max 121 C, 15+/-1 PSIG, RH=100% 100 hrs Normal: 2 lots Green: 1 lot 165 pcs 0 50+5 pcs / lot 96 hrs (Note B**) Normal: 2 lots Green: 1 lot 165 pcs 0 50+5 pcs / lot Temperature Cycle -65 to 150 deg C, air to air, 0.5hr per cycle 250 / 500 cycles (Note B**) Normal: 2 lots Green: 1 lot 165 pcs 0 50+5 pcs / lot (Note B**) 3 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 AO4900and AO4900L burn-in data up to the published date. Note B: The pressure pot, temperature cycle and HAST reliability data for AO4900L comes from the AOS generic green compound package qualification data. IV. Reliability Evaluation FIT rate (per billion): 7.20 MTBF = 15854 years 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 (AO4900). Failure Rate Determination is based on JEDEC Standard JESD 85. FIT means one failure per billion hours. 2 9 Failure Rate = Chi x 10 / [2 (N) (H) (Af)] = 1.83 x 10 9 8 MTBF = 10 / FIT =1.39x 10 hrs = 15854 years 9 / [2 (492) (1000) (258.24)] = 7.20 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 = 55C) 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 = Boltznan’s constant, 8.617164 X 10E -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 Contacts: Wei Liu Engineer of Failure Analysis and Reliability [email protected] Fred Chang Manager of Failure Analysis and Reliability [email protected] Wilson Ma Senior Director of Quality Assurance [email protected] 5