A high linearity current-controlled CMOS relaxation oscillator with frequency self-calibration technique.

A complementary metal oxide semiconductor relaxation oscillator adopting a new frequency self-calibration technique (FSCT) to improve the linearity is proposed in this paper. The FSCT can detect the peak voltage of the timing capacitor when start-up and change the reference voltage adaptively. Then, the non-linearity of the oscillator caused by the delay of the control circuit and the offset voltage of the comparator can be reduced obviously. The proposed relaxation oscillator with typical frequency of 5 MHz is implemented in 0.5 μm Silicon-On-Insulator Bipolar-CMOS-DMOS process. Measured results show that <0.79% non-linearity in the current-frequency transfer function from 0.1 to 10 MHz without trimming. [ABSTRACT FROM AUTHOR]