UWR Series
Single Output, High Reliability, 2" x 1", 6-10 Watt, DC-DC Converters
HALT Testing
Qualification
The goal of the accelerated-stress techniques used by Murata Power
Solutions is to force device maturity, in a short period of time, by exposing
devices to excessive levels of "every stimulus of potential value." We use
HALT (Highly Accelerated Life Testing) repeatedly during the design and
early manufacturing phases to detect potential electrical and mechanical
design weaknesses that could result in possible future field failures.
For each new product, electrical performance is verified via a comprehen-
sive characterization process and long-term reliability is confirmed via a
rigorous qualification procedure. The qual procedure includes such strenu-
ous tests as thermal shock and 500 hour life. Qual testing is summarized
below.
Qualification Testing
During HALT, prototype and pre-production DC/DC converters are sub-
jected to progressively higher stress levels induced by thermal cycling,
rate of temperature change, vibration, power cycling, product-specific
stresses (such as dc voltage variation) and combined environments. The
stresses are not meant to simulate field environments but to expose any
weaknesses in a product’s electro/mechanical design and/or assembly
processes. The goal of HALT is to make products fail so that device weak-
nesses can be analyzed and strengthened as appropriate. Applied stresses
are continually stepped up until products eventually fail. After corrective
actions and/or design changes, stresses are stepped up again and the cycle
is repeated until the "fundamental limit of the technology" is determined.
Qualification Test
HALT
Method/Comments
Murata Power Solutions in-house procedure
Max. rated temp., 1,000 hours
10 cycles, –55 to +125°C
High Temperature Storage
Thermal Shock
Temperature/Humidity
Lead Integrity
+85°C, 85% humidity, 48 hours
Murata Power Solutions in-house procedure
+70°C, 500 hours*
Life Test
Marking Permanency
End Point Electrical Tests
Murata Power Solutions in-house procedure
Per product specification
* Interim electrical test at 200 hours.
Murata Power Solutions has invested in a Qualmark OVS-1 HALT tester
capable of applying voltage and temperature extremes as well as 6-axis,
linear and rotational, random vibration. A typical HALT profile (shown above)
consists of thermal cycling (–55 to +125°C, 30°C/minute) and simultane-
ous, gradually increasing, random longitudinal and rotational vibration up
to 20G’s with load cycling and applied-voltage extremes added as desired.
Many devices in Murata Power Solutions' new A-Series could not be made
to fail prior to reaching either the limits of the HALT chamber or some previ-
ously known physical limit of the device.
In-Line Process Controls and Screening
A combination of statistical sampling and 100% inspection techniques
keeps our assembly line under constant control. Parameters such as
solder-paste thickness, component placement, cleanliness, etc. are statisti-
cally sampled, charted and fine tuned as necessary. Visual inspections are
performed by trained operators after pick-and-place, soldering and cleaning
operations. Units are 100% electrically tested prior to potting. All devices
are temperature cycled, burned-in, hi-pot tested and final-electrical tested
prior to external visual examination, packing and shipping.
We also use the HALT chamber and its ability to rapidly cool devices to
verify their "cold-start" capabilities.
100
Rapid Response to Problems
Murata Power Solutions employs an outstanding corrective-action system
to immediately address any detected shortcomings in either products or
processes. Whenever our assembly, quality or engineering personnel spot
a product/process problem, or if a product is returned with a potential
defect, we immediately perform a detailed failure analysis and, if necessary,
undertake corrective actions. Over time, this system has helped refine our
assembly operation to yield one of the lowest product defect rates in the
industry.
80
60
40
20
0
40
20
0
–20
–40
10
20
30
40
50
60
70
80
90
Test Time (minutes)
Typical HALT Profile
This product is subject to the following operating requirements
and the Life and Safety Critical Application Sales Policy:
Refer to: http://www.murata-ps.com/requirements/
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A.
ISO 9001 and 14001 REGISTERED
Murata Power Solutions, Inc. makes no representation that the use of its products in the circuits described herein, or the use of other
technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do not imply
the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without
notice.
© 2015 Murata Power Solutions, Inc.
www.murata-ps.com/support
MDC_UWR6-10W Series.E01 Page 6 of 6
