Abstract
A current to frequency convertor (CFC), fully integrated in aluminum gate p- channel enhancement/depletion MOS technology, is proposed. It is designed for measuring low level currents (10 to the -13th to 10 to the -18th A). A feedback loop is used to obtain good linearity (better than 5 percent). Experimentally, the CFC works in the range 5 x 10 to the -13th to 5 x 10 to the -8th A. Some nonlinearity problems are observed and explained in the paper. (Author)