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:
May. 15, 2001
Filed:
Oct. 21, 1999
Paul Dana Wohlfarth, Vernonia, OR (US);
Credence Systems Corporation, Fremont, CA (US);
Abstract
An integrated circuit (IC) tester includes a separate arbitrary waveform generator (AWG) for each input terminal of an IC to be tested. Each AWG generates a test signal input to the IC terminal that linearly ramps between discrete levels to approximate a smoothly varying waveform. Each AWG includes a digital-to-analog converter (DAC) formed by a set of N ramp generators, with each ramp generator producing output currents that ramp at adjustable rates between discrete levels in response to a change in state of an input waveform data bit. The output currents of all N ramp generators of the DAC, which have separately weighted magnitude levels, are summed and converted to a proportional voltage to produce the AWG's test signal.