MAX8538EEI Rev. A RELIABILITY REPORT FOR MAX8538EEI PLASTIC ENCAPSULATED DEVICES March 31, 2004 MAXIM INTEGRATED PRODUCTS 120 SAN GABRIEL DR. SUNNYVALE, CA 94086 Written by Reviewed by Jim Pedicord Quality Assurance Manager, Reliability Operations Bryan J. Preeshl Quality Assurance Managing Director Conclusion The MAX8538 successfully 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 V. ........Quality Assurance Information VI. .......Reliability Evaluation IV. .......Die Information .....Attachments I. Device Description A. General The MAX8538 is configured as a dual out-of-phase controller for point-of-load supplies. Each buck controller can source or sink up to 25A of current, while the termination reference can supply up to 15mA output. The MAX8538 uses constant-frequency voltage-mode architecture with operating frequencies of 200kHz to 1.4MHz. An internal high- bandwidth (25MHz) operational amplifier is used as an error amplifier to regulate the output voltage. This allows fast transient response, reducing the number of output capacitors. An all-N-FET design optimizes efficiency and cost. The MAX8538 has a 1% accurate reference. The controller uses a high-side current-sense architecture for current limiting. ILIM pins allow the setting of an adjustable, lossless current limit for different combinations of load current and RDSON. Alternately, more accurate overcurrent limit is achieved by using a sense resistor in series with the high-side FET. Overvoltage protection is achieved by latching off the high-side MOSFET and latching on the low-side MOSFET when the output voltage exceeds 17% of its set output. Independent enable, power-good, and soft-start features enhance flexibility. B. Absolute Maximum Ratings Item V+ to GND AVL, VL to GND PGND to GND FB_, EN_, POK_ to GND REFIN, VTTR, FREQ, SS_, COMP_ to GND BST_, ILIM_ to GND DH1 to LX1 DH2 to LX2 LX_ to BST_ LX_ to GND DL_ to PGND Operating Temperature Range Junction Temperature Storage Temperature Range Lead Temperature (soldering, 10s) Continuous Power Dissipation (TA = +70°C) 28-Pin QSOP Derates above +70°C 28-Pin QSOP Rating -0.3V to +25V -0.3V to +6V -0.3V to +0.3V -0.3V to +6V .-0.3V to (AVL + 0.3V) -0.3V to +30V -0.3V to (BST1 + 0.3V) -0.3V to (BST2 + 0.3V) -6V to +0.3V -2V to +25V -0.3V to (VL + 0.3V) -40°C to +85°C +150°C -65°C to +150°C +300°C 860mW 10.8mW/°C II. Manufacturing Information A. Description/Function: Dual-Synchronous Buck Controllers for Point-of-Load, Tracking, and DDR Memory Power Supplies B. Process: S8 (Standard 0.8 micron silicon gate CMOS) C. Number of Device Transistors: 5504 D. Fabrication Location: California, USA E. Assembly Location: Philippines or Thailand F. Date of Initial Production: January, 2004 III. Packaging Information A. Package Type: 28-Pin QSOP B. Lead Frame: Copper C. Lead Finish: Solder Plate D. Die Attach: Silver-Filled Epoxy E. Bondwire: Gold (1.3 mil dia.) F. Mold Material: Epoxy with silica filler G. Assembly Diagram: # 05-9000-0559 H. Flammability Rating: Class UL94-V0 I. Classification of Moisture Sensitivity per JEDEC standard J-STD-020-A: Level 1 IV. Die Information A. Dimensions: 140 x 80 mils B. Passivation: Si3N4/SiO2 (Silicon nitride/ Silicon dioxide) C. Interconnect: Aluminum/Si (Si = 1%) D. Backside Metallization: None E. Minimum Metal Width: 0.8 microns (as drawn) F. Minimum Metal Spacing: 0.8 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: B. Outgoing Inspection Level: Jim Pedicord (Manager, Reliability Operations) Bryan Preeshl (Managing Director of QA) Kenneth Huening (Vice President) 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 48 x 2 (Chi square value for MTTF upper limit) Temperature Acceleration factor assuming an activation energy of 0.8eV λ = 22.62 x 10-9 λ = 22.62 F.I.T. (60% confidence level @ 25°C) This low failure rate represents data collected from Maxim’s reliability monitor program. In addition to routine production Burn-In, Maxim pulls a sample from every fabrication process three times per week and subjects it to an extended Burn-In prior to shipment to ensure its reliability. The reliability control level for each lot to be shipped as standard product 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 any lot that exceeds this reliability control level. Attached Burn-In Schematic (Spec. # 06-6190) shows the static Burn-In circuit. Maxim also performs quarterly 1000 hour life test monitors. This data is published in the Product Reliability Report (RR-1M). B. Moisture Resistance Tests Maxim pulls pressure pot samples from every assembly process three times per week. Each lot sample must meet an LTPD = 20 or less before shipment as standard product. Additionally, the industry standard 85°C/85%RH testing is done per generic device/package family once a quarter. C. E.S.D. and Latch-Up Testing The PN02-1 die type has been found to have all pins able to withstand a transient pulse of ±<200V, 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 MAX8538EEI 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 48 0 77 0 0 Moisture Testing (Note 2) Pressure Pot Ta = 121°C P = 15 psi. RH= 100% Time = 168hrs. DC Parameters & functionality QFN 85/85 Ta = 85°C RH = 85% Biased Time = 1000hrs. DC Parameters & functionality 77 DC Parameters & functionality 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 9K 1K 1 28 2 27 3 26 4 25 5 24 6 23 7 22 8 21 9 20 10 19 11 18 12 17 13 16 14 15 -2.5V 4.7 uF 10 Ohms +20V 1 MEGHz 40 K 20 K 10 nF 10 nF 10 K DEVICES: MAX8537/8538/8539 PACKAGE: 28-QSOP MAX. EXPECTED CURRENT = 12mA (+20V), 250uA (-2.5V) DOCUMENT I.D. 06-6190 REVISION A MAXIM TITLE: BI 1 uF 10 uF DRAWN BY: TEK TAN NOTES: Circuit: MAX8537/8538/8539 (PN02) PAGE 2