A Fully Integrated Silicon-Carbide Sigma–Delta Modulator Operating up to 500 °C

This paper presents the first fully integrated sigma-delta modulator implemented in an in-house silicon carbide (SiC) bipolar technology for high-temperature applications. A second-order 1-b continuous-time architecture is adopted. Dual-loop compensation technique is employed to accommodate one clock period comparator delay. The circuits are designed to have enough margins without degrading the modulator's performance, considering the variation of device parameters over a large temperature range. The measurement results show that from room temperature to 500°C, the modulator's peak SNDR is constant around 30 dB at a clock speed of 512 kHz. The chip area of the modulator is 6.9 mm × 2.8 mm with one metal layer. It consumes around 1 W from a 15 V power supply. This paper demonstrates the feasibility to further develop highly integrated SiC bipolar junction transistor integrated circuits for extremely high-temperature sensing applications.