Analog circuits for thermistor linearization with Chebyshev-optimal linearity error

This paper investigates analog linearization circuits for NTC thermistors, and the theoretical limits to linearity performance. In theory, by using multiple identical thermistors, the circuit may have a linearity error that is arbitrarily small and optimal in the Chebyshev norm. This result also applies to many other impedance-type sensors (e.g. resistive, capacitive). Experimental data from a three-thermistor circuit shows approximately 16 mK (160 ppm) linearity over a span of 100degC, consistent with a theoretical limit of plusmn12 mK (120 ppm).