US 5557209

Patent Overview — US 5,557,209

Title: Identification of pin-open faults by capacitive coupling through the integrated circuit package

Patent number: US 5,557,209 A
Application number: US 08/400,787
Inventor(s): David T. Crook; Kevin W. Keirn; Ugur Cilingiroglu
Original assignee: Hewlett-Packard Co. (current assignee listed as Agilent Technologies Inc.)
Priority date: 1990-12-20
Filing date: 1995-03-07
Publication/grant date: 1996-09-17
Legal status (as listed): Expired – Lifetime; anticipated expiration 2013-09-17

Purpose. The invention generally relates to measuring and testing devices, particularly in-circuit testing of connections between integrated circuits (or other components) and a circuit assembly, such as a printed circuit board. A primary object is to provide improved apparatus and methods for testing the integrity of a connection between a pin of an electrical component and a printed circuit board or circuit assembly. The background notes that functional testing, in-circuit testing using a "bed of nails" fixture, and manufacturing defect analyzers each have limitations, and that the invention is predominantly directed to in-circuit testing of component-to-board connections.

Plain-language scope. The disclosed system measures the integrity of an electrical contact between a component connection pin and a circuit assembly. It includes: means for supplying an electrical signal; measuring means for measuring a parameter indicative of a capacitance associated with the pin-to-board connection; a conductive electrode connected to the measuring means and having a surface placed in proximity to a surface of the connection pin; an electrical connection from the signal-supplying means output to the pin under test; and an electrical connection between at least one other node of the circuit assembly and the common signal return. Preferred embodiments include error-indicating means when the measured parameter is outside predetermined limits; a measurement below a low limit indicates an open pin, while measurements exceeding a high limit indicate other faults such as an open ground or power pin. The measuring means may measure current or voltage between the electrode and common signal return, and the signal-supplying and measuring connections may be interchanged. Current-measuring embodiments may hold the measurement connection to a virtual ground, implemented with conventional operational amplifier circuitry.

Source: https://patents.google.com/patent/US5557209/en

What the excerpt does not establish. The supplied text is excerpted and omits the full claims, detailed description, and drawings. It does not establish the complete claim scope, the full list of cited prior art, prosecution history, or the accuracy of the listed assignees, legal status, or priority assumptions (which the source itself labels as assumptions, not legal conclusions).