A temperature-compensated differential VFC in 1.8 V–0.18 μm CMOS

This paper presents a new CMOS differential voltage-to-frequency converter (VFC) which targets front-end sensor interfacing in wireless sensor network applications. The proposed VFC, designed in a low-cost 0.18 μm CMOS technology supplied at 1.8 V, shows 0–1 MHz output frequency for 0–1.2 V differential input operation with nonlinearity error less than 0.4% and power consumption less than 0.4 mW. A temperature compensation technique keeps the error below 5.3% over all the frequency range for a (−20 ∘C,+120 ∘C) span.