Temperature sensor using BJT-MOSFET pair

A temperature sensor using the cascade configuration of a pnp bipolar junction transistor (BJT) and a p-type metal-oxide-semiconductor field effect transistor (PMOSFET) was designed and measured. Under a biasing current proportional to absolute temperature for a pnp BJT and a temperature-stable biasing current for a PMOSFET, the plots of emitter-base and source-gate bias voltages against temperature show nearly complementary nonlinear characteristics. Therefore, a temperature sensor of which the output is the sum of the two bias voltages will exhibit good linearity. For a temperature range from 0 to 125°C, the fabricated temperature sensor has the sensitivity of −3.39 mV/°C or so with linearity up to 99.996%.