Temperature Stable Ring Oscillator Based on the Mismatch Compensation of the Biasing Current

In this paper, a low temperature coefficient (TC) current reference using the mismatch compensation method is proposed. The temperature independent reference current is generated by scaling the W/L ratio of voltage mirror and adjusting the difference in biasing resistances. The basing current dependent TC and the optimum design strategies for MOSFET and resistors will be discussed in the following. The current reference has been fabricated in CSMC 0.35μm CMOS process. SPICE simulation results show that a minimums TC of the current reference is 5.6ppm/oC within the range of -40oC~125oC, and the output current is about 6μA. The experimental results suffer from a considerable degradation due to practical accuracy control limitation.