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 0.01 mm , 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 800 muW to 1.2 mW for temperatures ranging between -20degC to 80degC. It has been implemented using TSMC 0.18 mum technology.