We present a sigma-delta modulator in a standard CMOS process that is designed to operate over a wide temperature range from -55 ºC to 225 ºC. The circuit is implemented using IBM 0.13μm CMOS technology with 2.5V power supply. Constant-gm biasing technique and other design considerations are applied to compensate performance degradation over temperature variation. Simulation results show that the modulator offers a minimum ENOB of 14 bits over the desired wide temperature range