17.4 CMOS impedance analyzer for nanosamples investigation operating up to 150MHz with Sub-aF resolution

Impedance analyzers find an important role in nanoscience and in biological research as a tool to access electrical and physical parameters of the matter as well as to enhance the read-out performance in sensor applications. Needs are emerging to perform impedance spectroscopy on a wide frequency range. Electrical assessment of the cell metabolism, for example, requires a frequency of investigation of about 100 MHz for the signal to traverse the cell membrane and to access the cytoplasm. Bench-top impedance analyzers exist that cover such a wide frequency range but they are bulky, expensive and have inadequate resolution for the high impedance shown by many nanosamples and semi-insulating biological molecules. Recent compact analyzers based on custom CMOS chips are mainly focused on low-power solutions with sub-MHz ranges or highly multichannel applications. Here we present a fully-integrated current-to-admittance converter operating from 1kHz to 150MHz with the low noise level of other solutions operating at much lower frequencies.