Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – Of individual circuit component or element
Reexamination Certificate
2008-02-08
2009-08-04
Karlsen, Ernest F (Department: 2829)
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
Of individual circuit component or element
C324S601000, C326S030000, C702S107000
Reexamination Certificate
active
07570071
ABSTRACT:
Substantially-accurate calibration of output impedance of a device-under-test (DUT) to within a predetermined range of allowable impedance. The DUT is part of a source series terminated (SST) serial link transmitter, in which two branches of parallel transistors each provide an impedance value when particular transistors of the parallel branch are turned on. The impedance value is added to a series-connected resistor to provide the output impedance. The DUT consists of one branch of parallel transistors in series with a resistor. Output impedance of the DUT is compared to the resistance of a reference resistor, and the comparator provides a control signal based on whether the output impedance falls within the pre-set percentage variance of the reference resistance. The control signal is processed by a FSM (finite state machine) that individually turns on or off the transistors within the parallel branch until the DUT impedance value falls within the desired range.
REFERENCES:
patent: 6807650 (2004-10-01), Lamb et al.
patent: 6940303 (2005-09-01), Vargas
patent: 6958613 (2005-10-01), Braun et al.
patent: 7386410 (2008-06-01), Boskovic
patent: 2001-024497 (2001-01-01), None
Clements Steven M.
Cornwell William P.
Cox Carrie E.
Cranford, Jr. Hayden C.
Norman Vernon R.
Dillon & Yudell LLP
International Business Machines - Corporation
Karlsen Ernest F
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