The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 08, 2000
Filed:
Dec. 18, 1998
Charles R Erickson, Fremont, CA (US);
Brian D Erickson, Soquel, CA (US);
Xilinx, Inc., San Jose, CA (US);
Abstract
A method and structure for testing static signal levels on an integrated circuit device using an electron beam deflection device. Each static signal is applied to a first terminal of a switch, such as an AND gate, an OR gate, or a pass transistor. An alternating control signal of approximately 1 MHz is transmitted to a second terminal of the switch such that the switch generates an output signal that is either constant (if the static signal is at a first level), or has a frequency equal to that of the alternating control signal (if the static signal is at a second level). The output signal is transmitted to a pad located on an exposed surface of the integrated circuit, where an electron beam deflection device is utilized to determine the static signal level by detecting the presence or absence of an alternating signal. A method for determining the voltage level of a signal includes applying the signal to the gate of a transistor and an alternating control signal to an input terminal. An electron beam deflection device is then utilized to measure the voltage level of a signal generated at an output terminal of the transistor. The voltage level of the signal is then calculated by adding the measured voltage level and a threshold voltage of the transistor.