Flexible, automated diagnostic solutions to help people solve circuit card problems.
Designing Circuit Boards for Test
As boards become more complex the ability to test with traditional methods and systems becomes more
difficult. In some cases, the boards and their components are so dense that revolutionary test methods are
necessary to provide adequate fault coverage and diagnostic ability. This is particularly true where BGA
technology is selected and it is necessary to test the board using virtual test points. The design then
needs to be analyzed to understand the degree of fault coverage under these design conditions. Design For
Test is where component selection and circuit design are evaluated for their testability during the
development process.
Philosophy
DFT not only helps design engineers avoid wrong or weak implementations of
boundary scan, but also helps utilize multifaceted benefits of boundary scan in
testing products and programming devices. Where a commitment is made to
boundary scan ö an effective DFT strategy is intended to help prevent engineering
changes, which may result if testability is not adequately addressed earlier during
the design cycle. With boundary scan becoming a central process in many board test
and programming applications, attention to DFT and adherence to proper design
practices has become essential for successful launch and production of many new
products.
Huntron DFT Services
In reality many customers are faced with significant obstacles to the full adoption of
the Design for Test philosophy. This may be due to size of the organization where
in-house DFT expertise is not possible, application requirements force selection of
components that are not suited for boundary scan and/or the pace of product
development did not allow the incorporation of DFT into the initial design
specifications.
Huntron offers the customer a service to evaluate the design to determine the
degree of fault coverage that the design allows. Provided specific data is available,
Huntron professionals will analyze the boundary scan potential of the board. This
may even include trial tests to evaluate circuit behavior to get a handle on how many
of the nets will be covered by a boundary scan test. A test coverage report will be
provided to the customer that will outline recommendations on what changes could
be made to the board. If necessary, Huntron will also provide the final boundary
scan test as part of the DFT Services.
The objective of Huntron DFT Services is to help the customer remove problems and
achieve the highest level of fault coverage possible given the design of the board.
Not all boards that are designed for boundary scan will immediately lend themselves
to high fault coverage. Huntron DFT Services provide the ability to get feedback and
make decisions on how to overcome this short coming and maximize the testability
potential of the design.
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