MAXIM MAX1920

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