A CMOS low-distortion switched capacitor oscillator with instantaneous start-up

Experimental results on the oscillator indicate that good accuracy, low distortion, and instantaneous start-up are achieved. The sinusoidal oscillator has been fabricated in a 3-/spl mu/m CMOS double-poly process. The circuit is ideally suited for audio frequency applications such as DTMF tone generators and FSK modems. Further improvements in accuracy are expected if nonideal effects such as infinite op-amp gain and bandwidth and switch imperfections are taken into account.