A 16MHz RC Oscillator with a Frequency Inaccuracy of 24ppm/°C from −40°C to 125°C Adopting Only Positive Temperature Coefficient Resistors

A relaxation oscillator adopting only positive temperature coefficient resistors is presented in this paper. Two resistors with positive temperature coefficients are utilized to compensate for the resistance temperature drift by making the charging initial voltage of RC circuit follow the value change of the resistor in the charging branch. Designed in a 40nm CMOS process, the proposed RC relaxation oscillator operates at 16MHz, with a frequency inaccuracy of 24ppm/°C from -40°C to 125°C, and a power consumption of 3.125nW/kHz.