UWR Series
Single Output, High Reliability, 2" x 2", 14-20 Watt, DC/DC Converters
Design for Reliability
DATEL has invested in a Qualmark OVS-1 HALT tester capable of applying
voltage and temperature extremes as well as 6-axis, linear and rota-
Design for Reliability is woven throughout our multi-phased, new-product-
development process. Design-for-reliability practices are fully documented
and begin early in the new-product development cycle with the following
goals:
1. To work from an approved components/vendors list ensuring the use of
reliable components and the rigorous qualification of new components.
2. To design with safety margins by adhering to a strict set of derating
guidelines and performing theoretical worst-case analyses.
3. To locate potential design weaknesses early in the product-development
cycle by using extensive HALT (Highly Accelerated Life Testing).
4. To prove that early design improvements are effective by employing a
thorough FRACA (Failure Reporting Analysis and Corrective Action)
system.
tional, random vibration. A typical HALT profile (shown above) consists of
thermal cycling (–55 to +125°C, 30°C/minute) and simultaneous, gradually
increasing, random longitudinal and rotational vibration up to 20G’s with
load cycling and applied-voltage extremes added as desired. Many devices
in DATEL’s new A-Series could not be made to fail prior to reaching either
the limits of the HALT chamber or some previously known physical limit of
the device. We also use the HALT chamber and its ability to rapidly cool
devices to verify their "cold-start" capabilities.
Qualification
For each new product, electrical performance is verified via a comprehensive
characterization process and long-term reliability is confirmed via a rigorous
qualification procedure. The qual procedure includes such strenuous tests as
thermal shock and 500 hour life. Qual testing is summarized below.
Qualification Testing
HALT Testing
The goal of the accelerated-stress techniques used by DATEL 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 Acceler-
ated 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.
Qualification Test
HALT
Method/Comments
DATEL in-house procedure
Max. rated temp., 1,000 hours
10 cycles, –55 to +125°C
+85°C, 85% humidity, 48 hours
DATEL in-house procedure
+70°C, 500 hours*
High Temperature Storage
Thermal Shock
Temperature/Humidity
Lead Integrity
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.
Life Test
Marking Permanency
End Point Electrical Tests
DATEL in-house procedure
Per product specification
* Interim electrical test at 200 hours.
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.
Typical HALT Profile
100
80
60
40
20
0
Rapid Response to Problems
40
DATEL employs an outstanding corrective-action system to immediately
address any detected shortcomings in either products or processes. When-
ever 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.
20
0
–20
–40
10
20
30
40
50
60
70
80
90
Test Time (minutes)
USA:
Mansfield (MA), Tel: (508) 339-3000, email: sales@murata-ps.com
Toronto, Tel: (866) 740-1232, email: toronto@murata-ps.com
Canada:
UK:
Milton Keynes, Tel: +44 (0)1908 615232, email: mk@murata-ps.com
Montigny Le Bretonneux, Tel: +33 (0)1 34 60 01 01, email: france@murata-ps.com
München, Tel: +49 (0)89-544334-0, email: munich@murata-ps.com
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A.
Tel: (508) 339-3000 (800) 233-2765 Fax: (508) 339-6356
France:
Germany:
Japan:
Tokyo, Tel: 3-3779-1031, email: sales_tokyo@murata-ps.com
Osaka, Tel: 6-6354-2025, email: sales_osaka@murata-ps.com
www.murata-ps.com email: sales@murata-ps.com ISO 9001 and 14001 REGISTERED
12/04/08
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
China:
Shanghai, Tel: +86 215 027 3678, email: shanghai@murata-ps.com
Guangzhou, Tel: +86 208 221 8066, email: guangzhou@murata-ps.com
notice.
© 2008 Murata Power Solutions, Inc.
Singapore: Parkway Centre, Tel: +65 6348 9096, email: singapore@murata-ps.com
www.murata-ps.com
Technical enquiries email: sales@murata-ps.com, tel: +1 508 339 3000
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