| Summary: | Conventionally, the performances of Analog and Mixed-Signal (AMS)
circuits have been characterized using specification-based functional tests. In
these test methods, the correct functionalities of AMS circuits are verified
by measuring pre-determined specification parameters of AMS circuits. The
conventional test methods provide accurate test results by using various test
equipments which generate functional test signals and capture the test responses
externally. However, due to rapid increase in the performance of AMS
circuits in recent years, the conventional test methods face various challenges
in the aspects of test cost, test time and testability.
The goal of this dissertation is to develop innovative functional test
methods for AMS circuits which are aimed at reducing the test cost and test
time while providing comparable test accuracy to the conventional test methods.
To achieve this goal, efforts have been made to explore the characteristics of AMS circuits in a system level and to research efficient performance characterization
methods based on the system level modeling of Devices Under Test
(DUTs). As a part of these efforts, the pseudorandom test methods for nonlinear
AMS circuits have been developed. In these methods, the pseudorandom
signal is used to excite the DUT and to generate the test response which has
sufficient information to characterize DUT performances. The pseudorandom
test methods use the Volterra series model to capture the nonlinear behaviors
of AMS circuits and to calculate various specification parameters of the
DUT using the pseudorandom test response. In doing so, the performances of
nonlinear AMS circuits can be characterized straightforwardly and accurately
using a low-cost test setup. Also, in an effort to reduce the test time, parallel
test methods of AMS circuits have been developed in which multiple DUTs
are tested simultaneously by sharing a common test setup. In these methods,
the test responses generated from different DUTs are combined together and
the resulting composite test response is used to characterize the performance
of each DUT individually. This will reduce the use of tester resources and will
increase the test throughput beyond the level limited by the test equipments.
The spectral characteristics of test stimulus are studied along with the system
level behavior of AMS circuits to develop the efficient parallel test methods.
Finally, in order to consider the practical issue of generating at-speed test stimuli
for high-speed DUTs using a low-cost test setup, a reconfigurable built-off
test interface is developed which can be used to generate various test patterns,
including high-speed pseudorandom signal, using a low-speed tester. === text
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