A 167.18 ppm/°C temperature coefficient, area efficient voltage reference using only MOS transistors

In this paper, design of a voltage reference circuit using only MOS transistors and without employing an operational amplifier is presented. A proportional to absolute temperature [PTAT] voltage and a PTAT current are designed then difference of the PTAT voltage and product of the PTAT current and resistor gives the temperature independent voltage. The advantages of both sub-threshold and strong inversion region operation of MOS transistors are exploited in the design. The voltage reference is implemented using standard CMOS 180 nm technology. The voltage reference provides a voltage of 224.3 mV consuming a quiescent current of 30 μA at room temperature. Post layout simulation results show that the proposed voltage reference has a temperature coefficient of 167.18 ppm/°C and varies only 3mV when there is a ±10% variation in supply voltage. The circuit occupies an area of only 93.6x32.6μm on the chip, making it suitable for area constraint applications.