MAX1921EUT Rev. A RELIABILITY REPORT FOR MAX1921EUT PLASTIC ENCAPSULATED DEVICES April 30, 2003 MAXIM INTEGRATED PRODUCTS 120 SAN GABRIEL DR. SUNNYVALE, CA 94086 Written by Reviewed by Jim Pedicord Quality Assurance Reliability Lab Manager Bryan J. Preeshl Quality Assurance Executive Director Conclusion The MAX1921 sucessfully meets the quality and reliability standards required of all Maxim products. In addition, Maxim’s continuous reliability monitoring program ensures that all outgoing product will continue to meet Maxim’s quality and reliability standards. Table of Contents I. ........Device Description II. ........Manufacturing Information III. .......Packaging Information IV. .......Die Information V. ........Quality Assurance Information VI. .......Reliability Evaluation ......Attachments I. Device Description A. General The MAX1921 step-down converter delivers over 400mA to outputs as low as 1.25V. This converter uses a unique proprietary current-limited control scheme that achieves over 90% efficiency. This device maintains extremely low quiescent supply current (50µA), and it’s high 1.2MHz (max) operating frequency permits small, low-cost external components. This combination makes the MAX1921 an excellent high-efficiency alternative to linear regulators in space-constrained applications. Internal synchronous rectification greatly improves efficiency and eliminates the external Schottky diode required in conventional step-down converters. The device also includes internal digital soft-start to limit input current upon startup and reduce input capacitor requirements. The MAX1921 provides factory-preset output voltages (see the Selector Guide) and is available in space-saving 6-pin SOT23 packages B. Absolute Maximum Ratings Item IN, FB, SHDN to AGND OUT to AGND, LX to PGND AGND to PGND OUT Short Circuit to GND Operating Temperature Range Junction Temperature Storage Temperature Lead Temperature (soldering 10s) Continuous Power Dissipation (TA = +70°C) 6-Pin SOT23 Derates above +70°C 6-Pin SOT23 Rating -0.3V to +6V -0.3V to (IN + 0.3V) -0.3V to +0.3V 10s -40°C to +85°C +150°C -65°C to +150°C +300°C 696mW 8.7mW/°C II. Manufacturing Information A. Description/Function: Low-Voltage, 400mA Step-Down DC-DC Converters in SOT23 B. Process: B8 C. Number of Device Transistors: 1467 D. Fabrication Location: California, USA E. Assembly Location: Philippines, Malaysia or Thailand F. Date of Initial Production: January, 2002 III. Packaging Information A. Package Type: 6-Lead SOT23 B. Lead Frame: Copper C. Lead Finish: Solder Plate D. Die Attach: Non-Conductive Epoxy E. Bondwire: Gold (1.3 mil dia.) F. Mold Material: Epoxy with silica filler G. Assembly Diagram: # 05-3501-0021 H. Flammability Rating: Class UL94-V0 I. Classification of Moisture Sensitivity per JEDEC standard JESD22-A112: Level 1 IV. Die Information A. Dimensions: 60 x 41 mils B. Passivation: Si3N4/SiO2 (Silicon nitride/ Silicon dioxide) C. Interconnect: Aluminum/Copper/Silicon D. Backside Metallization: None E. Minimum Metal Width: .8 microns (as drawn) F. Minimum Metal Spacing: .8 microns (as drawn) G. Bondpad Dimensions: 5 mil. Sq. H. Isolation Dielectric: SiO2 I. Die Separation Method: Wafer Saw V. Quality Assurance Information A. Quality Assurance Contacts: Jim Pedicord Bryan Preeshl Kenneth Huening (Reliablity Lab Manager) (Executive Director of QA) (Vice President) B. Outgoing Inspection Level: 0.1% for all electrical parameters guaranteed by the Datasheet. 0.1% For all Visual Defects. C. Observed Outgoing Defect Rate: < 50 ppm D. Sampling Plan: Mil-Std-105D VI. Reliability Evaluation A. Accelerated Life Test The results of the 135°C biased (static) life test are shown in Table 1. Using these results, the Failure Rate (λ) is calculated as follows: λ= 1 = MTTF 1.83 192 x 4389 x 134 x 2 (Chi square value for MTTF upper limit) Thermal acceleration factor assuming a 0.8eV activation energy λ = 8.10 x 10-9 λ= 8.10 F.I.T. (60% confidence level @ 25°C) This low failure rate represents data collected from Maxim’s reliability qualification and monitor programs. Maxim also performs weekly Burn-In on samples from production to assure the reliability of its processes. The reliability required for lots which receive a burn-in qualification is 59 F.I.T. at a 60% confidence level, which equates to 3 failures in an 80 piece sample. Maxim performs failure analysis on lots exceeding this level. The following Burn-In Schematic (Spec. #06-5924) shows the static circuit used for this test. Maxim also performs 1000 hour life test monitors quarterly for each process. This data is published in the Product Reliability Report (RR-1M). B. Moisture Resistance Tests Maxim evaluates pressure pot stress from every assembly process during qualification of each new design. Pressure Pot testing must pass a 20% LTPD for acceptance. Additionally, industry standard 85°C/85%RH or HAST tests are performed quarterly per device/package family. C. E.S.D. and Latch-Up Testing The PM02 die type has been found to have all pins able to withstand a transient pulse of 1000V, per MilStd-883 Method 3015 (reference attached ESD Test Circuit). Latch-Up testing has shown that this device withstands a current of ±250mA. Table 1 Reliability Evaluation Test Results MAX1921EUT TEST ITEM TEST CONDITION Static Life Test (Note 1) Ta = 135°C Biased Time = 192 hrs. FAILURE IDENTIFICATION PACKAGE DC Parameters & functionality SAMPLE SIZE NUMBER OF FAILURES 134 0 77 0 0 Moisture Testing (Note 2) Pressure Pot Ta = 121°C P = 15 psi. RH= 100% Time = 168hrs. DC Parameters & functionality SOT 85/85 Ta = 85°C RH = 85% Biased Time = 1000hrs. DC Parameters & functionality 77 DC Parameters 77 Mechanical Stress (Note 2) Temperature Cycle -65°C/150°C 1000 Cycles Method 1010 Note 1: Life Test Data may represent plastic DIP qualification lots. Note 2: Generic Package/Process data 0 Attachment #1 TABLE II. Pin combination to be tested. 1/ 2/ Terminal A (Each pin individually connected to terminal A with the other floating) Terminal B (The common combination of all like-named pins connected to terminal B) 1. All pins except VPS1 3/ All VPS1 pins 2. All input and output pins All other input-output pins 1/ Table II is restated in narrative form in 3.4 below. 2/ No connects are not to be tested. 3/ Repeat pin combination I for each named Power supply and for ground (e.g., where VPS1 is VDD, VCC, VSS, VBB, GND, +VS, -VS, VREF, etc). 3.4 Pin combinations to be tested. a. Each pin individually connected to terminal A with respect to the device ground pin(s) connected to terminal B. All pins except the one being tested and the ground pin(s) shall be open. b. Each pin individually connected to terminal A with respect to each different set of a combination of all named power supply pins (e.g., VSS1, or VSS2 or VSS3 or VCC1 , or VCC2 ) connected to terminal B. All pins except the one being tested and the power supply pin or set of pins shall be open. c. Each input and each output individually connected to terminal A with respect to a combination of all the other input and output pins connected to terminal B. All pins except the input or output pin being tested and the combination of all the other input and output pins shall be open. TERMINAL C R1 R2 S1 TERMINAL A REGULATED HIGH VOLTAGE SUPPLY S2 C1 DUT SOCKET SHORT TERMINAL B TERMINAL D Mil Std 883D Method 3015.7 Notice 8 R = 1.5kΩ C = 100pf CURRENT PROBE (NOTE 6) ONCE PER SOCKET ONCE PER BOARD 5K 1 8 2 7 3 6 4 5 5 OHMS 0.1 uF +5V 0.1 uF 100 uF 5K DEVICES: MAX1920/1921 PACKAGE: 8-uMAX MAX. EXPECTED CURRENT = 1.5mA DOCUMENT I.D. 06-5924 REVISION A MAXIM DRAWN BY: TEK TAN NOTES: TITLE: BI Circuit (MAX1920/1921) PAGE 2 OF 3