Research On Three-position Integrated Common-mode Noise Suppression Filter

In the era of information transmission,multi-function,miniaturized high-speed transmission system,high-speed interface demand and research and development difficulties are increasing day by day.Common-mode noise suppression device is a necessary part of high-speed transmission system.It is difficult to realize its wide bandwidth,high noise suppression ability,high quality transmission signal and miniaturized high-performance device.Three-dimensional integration technology can not only reduce the traditional interconnection delay and loss problems,but also provide strong support for the design of micro passive devices.Based on the characteristics of low loss and miniaturization of 3D integration technology and from the perspective of good differential mode equivalent response,three different common-mode noise suppression filter structures are proposed in this paper.The main work contents are as follows:1.Based on 3D integration technology and the design principle of common-mode noise filter,a sixth-order common-mode noise filter is designed by using the equal delay line analog signal transmission channel.According to the equal delay line design method,the circuit parameters were calculated and the topology structure was built by ADS software.The passive device structure was determined by Q3D Extractor simulation software,and the sum full wave simulation was set up in the finite element HFSS electromagnetic simulation software.The results show that the filter area is only 290×320μm2,the common-mode noise suppression is more than 10dB in the bandwidth of 3.8～8.85GHz,and the fractional bandwidth is 80%.The bandwidth of difference signal loss<-3dB is 0～8.6GHz.The difference signal integrity is analyzed by using time domain eye map.Compared with the ideal circuit,the signal jitter changes within 2-3ps.The deviation of eye height and noise is only 0.06V and 0.038V respectively.2.Based on the 3D integration technology and the design principle of common-mode noise filter,the fifth and seventh order common-mode noise filter is proposed by using the low-pass filter to simulate the signal transmission channel.The topology parameters were calculated according to the LPF design method.By comparing the responses of common-mode noise suppression filters designed by different LPF,Chebyshev LPF was selected to design the common-mode noise suppression filter.The cu-off frequency of the fifth order LPF is 30GHz,and the area of the common-mode noise suppression filter is only 400×430μm2.The simulation results show that the common-mode noise suppression is more than 10dB,the fractional bandwidth is 103%,and the suppression bandwidth is 17.79 GHz in the bandwidth of 8.41～26.2GHz.Differential signal cutoff frequency(-3dB)at 26.25GHz.Considering the higher order circuit to achieve better filter performance,the circuit and structure of the seventh-order common-mode noise suppression filter are constructed and simulated.The results show that the cutoff frequency of the differential mode signal is 17.8GHz when the size is only 250×430μm2.Common mode noise suppression of>10dB is achieved in the frequency band of 3.3～11.8GHz,the suppression bandwidth is 8.5GHz,and the fractional bandwidth reaches 112.6%.Compared with the common-mode noise suppression filter based on all-pass filter,the circuit and structure are more concise,and the bandwidth fraction and signal integrity bandwidth are better.Compared with similar filters at home and abroad,the proposed three structures have great advantages in size.