An Efficient Time-Domain Sensitivity Analysis for Analog and RF Design

J. Dobeš, S. Matějka, and K. Ulovec (Czech Republic)


Sensitivity analysis, implicit integration algorithm, analog multiplier, four-quadrant RF mixer, temperature analysis.


The standard programs have limited modes of the sensi tivity analysis: PSPICE contains a static mode only and SCEPTRE includes frequency-domain and static modes. However, many RF systems use symmetrical structures for enhancing the properties of the circuits. For such systems, the static sensitivities are zero in principle and therefore the time-domain sensitivity analysis is to be used. In the paper, a new recurrent formula for the time-domain sensi tivity analysis is derived which uses the by-products of an implicit integration algorithm. As the selected integration algorithm is more flexible than the Gear's one used in the PSPICE family, the sensitivity analysis is more efficient in comparison with the standard CAD tools. An implemen tation of the method is demonstrated using the analysis of a low-voltage four-quadrant RF multiplier--we propose to use it as a part of an OFDM modulator as well. A nonstan dard temperature sensitivity analysis is also demonstrated.

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