A temperature sensing front-end using CMOS substrate PNP transistors

A temperature sensing front-end of temperature sensor based on CMOS substrate pnp transistors is presented. It uses ΔV_BE which is proportional to absolute temperature (PTAT) to realize temperature measurement. Non-idealities of the resulting PTAT voltage are analyzed and circuit compensation techniques for these non-idealities are introduced. The circuit is implemented in Chartered 0.18μm CMOS technology, and by taking the reverse Early effect into account. Experimental results show that temperature accuracy which is extracted from experiment can reach ±0.5°C in the range of -40°C to 40°C.