I am sensing over a range of 0.5pF (1.0 to 1.5pF) using the recommended components: 18uH + 33pF
The bulk cap of 33pF is a big offset to the system and with COG capacitors the temperature drift is 30ppm/K = 1ff/K
Is it possible to improve the temperature stability for example using an analog switch or are there any recommendations to reduce the bulk capacitance ?
Do you have any data on long term drift in components at extended temperatures - e.g. 125C ?
As the sensing is to steel, would sensing the inductance be a better option, or any suggestions to alternative circuits to the FDC2xxx devices.
Thanks
