Compact BJT/JFET PTAT
Slavko Amon, M. Možek, D. Vrtačnik, Drago Resnik, U. Aljančič, M. Cvar · 2002
Research on a new compact BJT/JFET PTAT temperature sensor structure is reported. Equations describing sensor response are derived. The effects of important structure parameters are included. Measurements on fabricated test PTAT structures revealed reasonably good temperature response in a wide temperature range (-130/spl deg/C to +100/spl deg/C). At low temperatures (measured down to -200/spl deg/C), considerable deviation from ideal PTAT response was detected. It is shown that deviation is due to the reduction of constant diode ideality factor n region, related to the free carriers freeze-out effect. JFET current generators, in spite of appreciable temperature dependence, do not include excessive nonlinearity.