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Method for testing via a modular active-probe device

IP.com Disclosure Number: IPCOM000019062D
Publication Date: 2003-Aug-27
Document File: 4 page(s) / 99K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a modular active-probe device. Benefits include an improved test environment and improved functionality.

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Method for testing via a modular active-probe device

Disclosed is a method for a modular active-probe device. Benefits include an improved test environment and improved functionality.

Background

         Several testing methodologies are commonly used in PCB board socket/connectors like top-side probing, boundary scan (BSCAN) testing on a CPU socket with a processor present, implementing field-effect transistor (FET) through connector testing (TCT) module testing and other solutions. Topside probing has problems like expensive fixture cost, long fixture fabrication lead time, not reusable due to not having a modular design. Whereas BSCAN test does not provide 100% coverage due to loss of power and ground pin detection. The FET TCT module might be too big for certain types of fixtures and may lead to BGA open joints. Additionally, power-up testing is required for BSCAN and FET testing.

         For socket/connector testing, daisy chain is still the easy way to detect the manufacturing fault. During socket testing with a daisy-chain configuration, isolation is required. All the daisy-chain connections must be set up before testing can begin. However, connection to the board circuitry must be isolated. During automated testing, a mechanical method of isolating the test probes is often used, which is expensive to implement/maintain and consumes a large amount of test time. Conventionally, electrical isolation for test probes from the DUT does not exist. The only means is to use a mechanical-assist isolation method, such as pneumatic-block or dual-stage actuation. However, the mechanical solution also has limitations as it is difficult (if not impossible) to isolate individual probe connections to the DUT.

         High transient nodes, such as a signal with a high dV/dT value, are sensitive to probe loading. Probe impedance easily changes the signal characteristics, causing malfunction to device-under-test (DUT) circuitry. For example, a DC-to-DC voltage converter that uses a pulse wave modulator is sensitive to probe loading on its circuitry. The test probes must be removed to ensure the DUT functions correctly, losing test coverage on the disconnected nodes.

         With conventional electronic components, high-frequency signal nodes are typically part of the design. High-impedance probes have become a requirement for product diagnosis and validation. However, during manufacturing test, these probes are not available and make high-frequency signal nodes untestable.

         Test probes are conventionally passive probes, which do not provide for signal amplification and high-impedance isolation.

General description

         The disclosed method is socket/connector testing via a modular active probes interface. The method includes an attachable/detachable module mounted on a test fixture probe/receptacle for signal isolation, amplification and active signal probing.

         The disclosed method is a modular design. Elements, such as the probe and snap-in active probe modules, can be easily replaced during...