A Novel CMOS Interface for Oxygen Sensors

This paper describes a CMOS interface for an oxygen sensor. It provides a differential to single-ended conversion with a good common mode rejection, a proper level shifting and an accurate voltage gain. The paper presents design considerations and measurements performed on an integrated test structure. The variation of the large-signal voltage gain is kept within ±10 % when the input common mode voltage ranges from ¿0.5 V to 1.5 V. The differential nonlinearity is better than ¿6 % to +2 % over an input differential signal range of ±0.5 V. These results meet the specifications required for automotive applications.