Abstract: An analog to digital converter circuit includes an isolation circuit, an input circuit including a resistor chain, a plurality of fixed threshold comparators, and an encoder. The resistor chain includes a plurality of resistors connected in series, the isolation circuit being configured to isolate a device supplying the analog input signal from the input circuit. The isolation circuit is connected to the input circuit at a top node of the resistor chain, and wherein 2N values of the analog input voltage are connected to inputs of the fixed threshold comparators to produce corresponding output signals. Methods of converting an analog signal to a digital signal are also described.

Abstract: Molecular recognition-based electronic sensor, which is gateless, depletion mode field effect transistor consisting of source and drain diffusions, a depletion-mode implant, and insulating layer chemically modified by immobilized molecular receptors that enables miniaturized label-free molecular detection amenable to high-density array formats. The conductivity of the active channel modulates current flow through the active channel when a voltage is applied between the source and drain diffusions. The conductivity of the active channel is determined by the potential of the sample solution in which the device is immersed and the device-solution interfacial capacitance. The conductivity of the active channel modulates current flow through the active channel when a voltage is applied between the source and drain diffusions. The interfacial capacitance is determined by the extent of occupancy of the immobilized receptor molecules by target molecules. Target molecules can be either charged or uncharged.