Characterization of temperature sensor using VT extractor circuit

The semiconductor (or IC for integrated circuit) temperature sensor is an electronic device fabricated in a similar way to other modern electronic semiconductor components such as microprocessors, diode, transistors, capacitors and etc. There are few temperature sensors being used in nowadays i.e diode type and threshold voltage (V_T) extractor type. Normally hundreds or thousands of devices are formed on single thin silicon wafers. These sensors share a number of characteristics - linear outputs, relatively small size, limited temperature range (-40 to +120degC typical), low cost, good accuracy if calibrated but also poor interchangeability. Often the semiconductor temperature sensors are not well designed thermally, with the semiconductor chip not always in good thermal contact with an outside surface. Some devices are inclined to oscillate unless precautions are taken. Provided the limitations of the semiconductor temperature sensors are understood, they can be used effectively in many applications. The most popular semiconductor temperature sensors are based on the fundamental temperature and current characteristics of the transistor. In this paper, the V_T extractor type sensor is going to be discussed and the characterization of output voltage to temperature scale will be show. The sensors are calibrated based on environment effect and use water as a medium to translate the temperature to voltage. Also, two kind of circuit being used i.e flex circuit and dual layer PCB. The comparison between these two approaches described in full in this paper.