A 6MHz CMOS reference clock generator with temperature and supply voltage compensation

A 6MHz CMOS reference clock generator is presented in 0.18um CMOS process. The proposed structure adopts a current starved type ring oscillator with low drop out (LDO), and temperature compensated current bias. This structure minimized the effects of supply and temperature to frequency error. The reference clock generator achieves frequency variation of less than ±0.26% against supply variation of 3V ~ 5V and ±0.22% against temperature variation of -20°C ~ 100°C.