Transients, FFT analysis and Physical design of multi stage Ring Oscillators using 0.3µm CMOS technology

Ring Oscillators are basic blocks of key digital modules like PLL, microprocessor or any other time related and memory driven circuits. The purpose of this paper is to compare transients and analyze FFT of multistage ring oscillators and physical design of the same. Additional DRC and NCC checks are applied on the design using 300 nm process technologies. Ring oscillator design presented is driven and controlled by a voltage bias that can be varied by SPICE code. Here a VCO based design is presented that had less floor plan area, lesser power dissipation and consumption and also providing better noise profile which is helpful and applicable for wideband analog mixed signal circuits. Ring Oscillators in this paper, 11 stages, 21 stages and 51 stages are presented. and suitable transients and FFT is done on the design. The paper will also consider a variety of design considerations which are SCMOS cell designs, supply or biasing circuitries and tool based implementation and SPICE based simulations of the multistage oscillator design.