AOS Semiconductor Product Reliability Report AO4914/AO4914L, rev D Plastic Encapsulated Device ALPHA & OMEGA Semiconductor, Inc 495 Mercury Drive Sunnyvale, CA 94085 U.S. Tel: (408) 830-9742 www.aosmd.com Apr 11, 2006 1 This AOS product reliability report summarizes the qualification result for AO4914. 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 AO4914passes 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 AO4914 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 DC-DC converters. A Schottky diode is co-packaged in parallel with the synchronous MOSFET to boost efficiency further Standard product AO4914 is Pb-free (meets ROHS & Sony 259 specifications). AO4914L is a Green Product ordering option. AO4914 and AO4914L are electrically identical. Absolute Maximum Ratings TA=25°C unless otherwise noted Parameter Symbol Max Q1 Max Q2 Units Drain-Source Voltage VDS 30 30 V Gate-Source Voltage VGS ±20 ±20 V ID 8.5 8.5 6.6 6.6 30 30 2 2 1.28 1.28 W -55 to 150 -55 to 150 °C Continuous Drain Current TA=25°C TA=70°C Pulsed Drain Current Power Dissipation TA=25°C TA=70°C IDM PD Junction and Storage Temperature Range TJ, TSTG Parameter Symbol Reverse Voltage VKA Continuous Forward Current TA=25°C TA=25°C TA=70°C Junction and Storage Temperature Range 30 3 Units V 2.2 TA=70°C Pulsed Forward Current Power Dissipation IF Maximum Schottky A IFM PD TJ, TSTG 20 A 2 1.28 W -55 to 150 °C 2 Thermal Characteristics MOSFET Q1 Maximum Junctiont ≤ 10s to-Ambient Maximum JunctionSteadyto-Ambient State Maximum JunctionSteadyto-Lead State Thermal Characteristics MOSFET Q2 Maximum Junctiont ≤ 10s to-Ambient Maximum JunctionSteadyto-Ambient State Maximum JunctionSteadyto-Lead State Thermal Characteristics Schottky Maximum Junctiont ≤ 10s to-Ambient Maximum JunctionSteadyto-Ambient State Maximum JunctionSteadyto-Lead State Symbol Typ Max 48 62.5 74 110 RθJL 35 40 Symbol Typ Max 48 62.5 74 110 RθJL 35 40 Symbol Typ Max 47.5 62.5 71 110 32 40 RθJA RθJA RθJA RθJL Units °C/W Units °C/W Units °C/W II. Die / Package Information: Process AO4914 AO4914L (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 8 lead SOIC Copper with Solder Plate Silver epoxy 2 mils Au wire Epoxy resin with silica filler 90/10 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 3 III. Result of Reliability Stress for AO4914 (Standard) & AO4914L (Green) Test Item Test Condition Time Point Solder Reflow Precondition Standard: 1hr PCT+3 cycle IR reflow@260°c Green: 168hr 85/85 THB+3 cycle IR reflow@260°c Temp = 150°c, Vgs=100% of Vgsmax 0hr HTGB Lot Attribution Total Sample size Number of Failures Standard: 49 lots Green: 16 lots 9625 pcs 0 168 / 500 hrs 13 lots 1066 pcs 0 1000 hrs (Note A*) 168 / 500 hrs 13 lots 1000 hrs (Note A*) 100 hrs Standard: 33 lots Green: 13 lots 77+5 pcs / lot HTRB Temp = 150°c, Vds=80% of Vdsmax 1066 pcs 0 77+5 pcs / lot HAST Pressure Pot 130 +/- 2°c, 85%RH, 33.3 psi, Vgs = 80% of Vgs max 121°c, 15+/-1 PSIG, RH=100% 2530 pcs 0 50+5 pcs / lot 96 hrs (Note B**) Standard: 49 lots Green: 16 lots 3575 pcs 0 50+5 pcs / lot Temperature Cycle DPA -65 to 150°c, air to air, 250 / 500 cycles (Note B**) Standard: 49 lots Green: 15 lots 3520 pcs 0 50+5 pcs / lot Internal Vision Cross-section X-ray CSAM (Note B**) 5 5 5 5 5 5 0 NA 5 5 0 NA 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 AO4914and AO4914L burn-in data up to the published date. Note B: The pressure pot, temperature cycle and HAST reliability data for AO4914and AO4914L comes from the AOS generic package qualification data. 4 IV. Reliability Evaluation FIT rate (per billion):3 MTTF = 38051years 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 (AO4914). Failure Rate Determination is based on JEDEC Standard JESD 85. FIT means one failure per billion hours. Failure Rate = Chi2 × 109 / [2 (N) (H) (Af)] = 1.83 × 109 / [2 (5 × 164) ×(168) (258) + 2 (3 × 164) × (500) (258) + 2 (5 × 164) × (1000) (258)] =3 MTTF = 109 / FIT = 3.3 x 108 hrs = 38051years 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 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