Component Value Calculations and Characterizations for Measurements in the IEEE 1149.4 Environment

This paper describes a measurement principle for calculating component values from measurements conducted under less than optimal conditions, as is the case in the IEEE Std 1149.4 environment. Also presented are equations that take into account switch resistances on the signal paths, the output resistance of the signal generator, and the loading effect caused by the input impedance of the voltmeter together with the pin capacitances in parallel to the voltmeter. In addition, the paper presents characterization methods to determine values for these impedances. The inaccuracies achieved in the impedance range from k? to M? are of the order of few percent.