An integrated circuit solution of thermal noise thermometer with cascaded pre-amplifier and 6-bit resolution analog-to-digital converter

A solution of thermal noise thermometer in integrated circuit (IC) is presented in this paper. By limiting the dynamic range and bringing in IC solution, bottlenecks of high resolution and high speed requirements are broken. In this design, a multi-stage pre-amplifier is added to magnify the noise and predictions of output noise power from different sources are given after mathematical analysis. Consequently, the design conditions of the amplifier for maintaining the thermometers accuracy are generated. A 6-bit resolution analog-to-digital converter will be used to sample the signal and statistical theories are explored to develop methods which help acquire power and temperature information from the sampled codes. The design concepts are eventually verified by simulations. After one-point calibration at 27°C, the integral non-linearity of this method is 0.59°C over a temperature range from -40°C to 105°C.