Temperature insensitive current reference for the 6.27 MHz oscillator

This paper describes a circuit, which generates temperature-independent bias currents. In this paper, low-temperature coefficient reference is presented. The circuit is firstly employed to generate a current reference with temperature compensation, then combining the opposite characteristic curve current reference to minimize the variation of temperature. The proposed circuit has been design by a 0.18μm CMOS technology process and using computer simulation to evaluate the thermal drift of the reference current. This current reference is used to provide a stable current for a current controlled oscillator(CCO). The proposed CCO achieves temperature coefficients of 22.3 ppm/°C in the temperature range between -25 and 75°C.