Design for Reliability
Design for Reliability is woven throughout our multi-phased, new-productde-
velopment 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 reli-
able components and the rigorous qualifi cation of new components.
2. To design with safety margins by adhering to a strict set of derating guide-
lines 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 thor-
ough FRACA (Failure Reporting Analysis and Corrective Action) system.
HALT Testing
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 fi eld failures.
During HALT, prototype and pre-production DC/DC converters are subjected to
progressively higher stress levels induced by thermal cycling, rate of tempera-
ture change, vibration, power cycling, product-specifi c stresses (such as dc
voltage variation) and combined environments. The stresses are not meant
to simulate fi eld 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 weaknesses can be analyzed and strength-
ened 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.
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 profi le (shown above) consists
of thermal cycling (–55 to +125°C, 30°C/minute) and simultaneous, gradu-
ally 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 reach-
ing 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.
Qualifi cation
For each new product, electrical performance is verifi ed via a comprehensive
characterization process and long-term reliability is confi rmed via a rigorous
qualifi cation procedure. The qual procedure includes such strenuous tests as
thermal shock and 500 hour life. Qual testing is summarized below.
10 20 30 40 50 60 70 80 90
40
20
0
Random Vibration (G's)
Temperature (°C)
Test Time (minutes)
100
80
60
40
20
0
–20
–40
Typical HALT Profi le
QUALIFICATION TESTING
Qualifi cation Test Method/Comments
HALT Murata Power Solutions in-house procedure
High Temperature Storage Max. rated temp., 1,000 hours
Thermal Shock 10 cycles, –55 to +125°C
Temperature/Humidity +85°C, 85% humidity, 48 hours
Lead Integrity Murata Power Solutions in-house procedure
Life Test +70°C, 500 hours*
Marking Permanency Murata Power Solutions in-house procedure
End Point Electrical Tests Per product specifi cation
TWR Models
High-Reliability,
2" x 1", 8-11 W, Triple Output DC/DC Converters
MDC_TWR8-11W.D03 Page 5 of 5
www.murata-ps.com/support
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. Specifi cations are subject to change without
notice. © 2015 Murata Power Solutions, Inc.
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansfi eld, MA 02048-1151 U.S.A.
ISO 9001 and 14001 REGISTERED
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/
