Design Reuse Of CMOS Analog Operational Amplifier

At present,the design of integrated circuits and systems based on IP core has been widely used.IP is usually divided into hard,soft and firm core.On the digital circuit,because the automatic synthesis technology is more mature,the three types of IP core have been widely used.But for the analog circuit design because of its low level of automation,the main application is the hard core.This only when the various performance parameters of the IP core perfectly matching designer application requirements,otherwise,we can not use such a hard core.Even if the circuit structure is not change,it is often required to redesign the circuit,when process or performance requirements of the general analog circuit change,which consuming a lot of time.In order to realize the circuit design based on IP in a broader sense,starting from the designed circuit,by changing the design parameters to get a new design as soon as possible,when application requirements or process changed.The analog circuit of CMOS,the design parameters are length and width of MOS pipe.The design process is usually referred to as a sizing process,such design reuse referred circuit resizing,which is the key of analog circuit design reuse.In this paper,we will study how to transplante the circuit module which has been designed in a certain process line to the new process by resizing under the condition that the main performance indexes are kept unchanged.In this paper,a new method to design reuse of circuit is presented.Similar with the previous work,the basic idea of the method is try to match the current and small signal transconductance GM,output conductance GDS of MOS tube before and after transplantation,so as to ensure the same key circuit performance index.Different is the specific implementation of the matching method.This is a method of solving the channel current,transconductance and output conductance equations based on BSIM model to overcome the problem of the error caused by the inaccurate model.In this paper,the two stage operational amplifier with Miller compensation,a single ended output folded cascode amplifier and a fully differential folded cascode amplifier with common mode feedback circuit are used as examples.Under the condition of 0.35?m technology a normal working circuit is designed.Then the circuit design was transplanted to 0.18?m process circuit.By comparing the parameters of the MOS tube and the performance of the circuit before and after transplantation,the feasibility of the design reuse method of the circuit are proved.