Design of a Novel Very-Low Input Capacitance High-Bandwidth Buffer for a Biomass Sensor

In this work, a high-bandwidth very-low input capacitance original topology buffer was designed. The proposed buffer circuitry is conceived as part of a novel noninvasive nonimmersed real-time dielectric spectroscopy biomass sensor. Both a circuital-based simulation model and an experimental printed circuit board (PCB) prototype were implemented and successfully tested. The buffer effective parasitic input capacitance was lowered to a 2% of its original value by means of power supply bootstrapping. This improvement will allow performing differential voltage measurements with the required accuracy and without compromising the necessary bandwidth.