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 R
DSON
. 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:
C. Number of Device Transistors:
D. Fabrication Location:
E. Assembly Location:
F. Date of Initial Production:
S8 (Standard 0.8 micron silicon gate CMOS)
5504
California, USA
Philippines or Thailand
January, 2004
III. Packaging Information
A. Package Type:
B. Lead Frame:
C. Lead Finish:
D. Die Attach:
E. Bondwire:
F. Mold Material:
G. Assembly Diagram:
H. Flammability Rating:
28-Pin QSOP
Copper
Solder Plate
Silver-Filled Epoxy
Gold (1.3 mil dia.)
Epoxy with silica filler
# 05-9000-0559
Class UL94-V0
I. Classification of Moisture Sensitivity
per JEDEC standard J-STD-020-A:
Level 1
IV. Die Information
A. Dimensions:
B. Passivation:
C. Interconnect:
D. Backside Metallization:
E. Minimum Metal Width:
F. Minimum Metal Spacing:
G. Bondpad Dimensions:
H. Isolation Dielectric:
I. Die Separation Method:
140 x 80 mils
Si
3
N
4
/SiO
2
(Silicon nitride/ Silicon dioxide)
Aluminum/Si (Si = 1%)
None
0.8 microns (as drawn)
0.8 microns (as drawn)
5 mil. Sq.
SiO
2
Wafer Saw
V. Quality Assurance Information
A. Quality Assurance Contacts:
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.
B. Outgoing Inspection Level:
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 Mil-
Std-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
FAILURE
IDENTIFICATION
SAMPLE
SIZE
NUMBER OF
FAILURES
PACKAGE
Static Life Test
(Note 1)
Ta = 135°C
Biased
Time = 192 hrs.
Moisture Testing
(Note 2)
Pressure Pot
Ta = 121°C
P = 15 psi.
RH= 100%
Time = 168hrs.
Ta = 85°C
RH = 85%
Biased
Time = 1000hrs.
DC Parameters
& functionality
48
0
DC Parameters
& functionality
QFN
77
0
85/85
DC Parameters
& functionality
77
0
Mechanical Stress
(Note 2)
Temperature
Cycle
-65°C/150°C
1000 Cycles
Method 1010
DC Parameters
& functionality
77
0
Note 1: Life Test Data may represent plastic DIP qualification lots.
Note 2: Generic Package/Process data
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