Design Of Current Controlled RC Oscillator

Along with the increasing use of portable operated devices,the need for low voltage and low power integrated circuit has also grown.The design of this dissertation is current controlled oscillators(CCO),this kind of oscillator is widely used in the applications such as microcontroller,portable biomedical devices,etc.In these applications the requirement for accuracy and stability are not very high.When the voltage and temperature change,the accuracy and stability of frequency could be realized by the way of trimming to meet the need of specification.In this design of current controlled oscillators,the basic kinds and principle of oscillator are introduced at first.Then,the reverse short-channel effect(RSCE) in 90 nm process is analyzed in this thesis.Entire topology and the sub block are designed in terms of the customer's requirements.Primarily,such typical blocks are analyzed as Band-gap reference,Bias circuit,OPA,Comparator,High accuracy current mirror.The UMC 90nm Low Leakage RVT CMOS process is used in this chip.The power voltage range is from 1.08V to 1.32V,the frequency of oscillator is 50MHz,duty cycle is 50%.The current and voltage reference with an excellent temperature character are also designed,the temperature range is from-40℃to 125℃.And the frequency of oscillator is adjustable.Based on the analysis of circuit theory and the circuit topology,every sub-block and the entire circuit are simulated by the EDA tool HSPICE,The simulation results meet the design specification or better.The theory has been verified.Then the layout,layout verification and backend simulation have been done.Finally,the analysis of simulation results prove that when the voltage of power changes from 1.08V to 1.32V and temperature changes from-40℃to 125℃,the typical of resistor is typical/min/max and corner are TT,SS,FF,SF,FS,the frequency,duty cycle,entire start-up time,entire current all meet the specification,the project of low variation,low start-up time,low power is achieved.