A Merged Window Comparator Based Relaxation Oscillator with Low Temperature Coefficient

A novel relaxation oscillator (ROSC) with a merged window comparator, an optimized parallel/series composite resistor and a reference generator on the basis of threshold monitoring circuit is presented. The ROSC achieves offset cancellation by adopting the merged window comparator. The optimized composite resistor is employed to reduce the output frequency temperature coefficient (T.C.) even in the presence of process variation. The oscillator is realized in 65nm CMOS process. At a supply voltage of 1.2V, the current consumption is 7.47 mu A. The simulated frequency T.C. is 14.69ppm/degrees C over the temperature range of -20 similar to 120 degrees C and the line sensitivity is 0.188%/V over the supply voltage range of 1.2 similar to 2.3V.