This paper presents the design of low power, low cost design of temperature sensor that has been designed keeping in view VLSI circuits and technology changes. The circuit occupies an area close to 0.01mm2, which is less than 1/100th of the area occupied by most of the previous circuits that use capacitors and A/D converters. Power dissipation of the circuit ranges from 800µW to 1.2mW for temperatures ranging between -20°C to 80°C. It has been implemented using TSMC 0.18µm technology.