A proposed temperature sensor is based on pure CMOS PTAT circuitry, a preamplifier and a sigma delta ADC capable of simple and efficient temperature sensor conversion to digital value. The designed PTAT circuit utilized temperature compensation technology to enhance the linearity. The temperature sensor, which occupies 0.475 mm2, is fabricated using the TSMC 0.18 μm one-poly six-metal (1P6M) process. Measurement results show that the senor consume 46uA with a 1.5 V supply at 100 sample/s at room temperature. The sensor operates from -50°C to 150°C, archiving a 3σ resolution of ±0.8°C.