Analysis Of Power Integrity In The High-speed Circuits

With the trend of increasingly higher operating clock frequency, faster signal edge rate, and lower power supply voltage and noise margin, circuit function may fail due to distortion signal. It is because that simultaneous switching noise(SSN) has become one of the significant challenges for the design of power distribution network(PDN) in the high speed digital circuits. SSN between the planes can excite resonances and becomes excessively large due to the resonant behavior of the power buses(built up by the power and ground planes). These power integrity(PI) problems related to the noise transmission within the printed circuit board(PCB) have been largely investigated, and different solutions have been proposed, such as decoupling capacitors, electromagnetic band gap(EBG) structures.This paper analyzes the EBG structures for the SSN suppression of PDN. Firstly, it describes the history of high-speed circuit and the development status at home and abroad. Secondly, the basic components of PDN are introduced, focusing on the principle of decoupling capacitors, design methods, installation and so on. Then design methods, noise sources and DC- drop of PDN are given. Thirdly, it analyzes the reasons for the formation of SSN and suppression methods along with their advantages and disadvantages. What’s more, Mushroom EBG structure and coplanar EBG structures are compared in structural characteristics, equivalent circuit model and SSN suppression characteristics. Meanwhile, the advantages and disadvantages of the two structures are discussed. Finally, a novel EBG structures with T-shaped slits is designed based on the theory of EBG structures. And the design features of the new EBG structure is described in detail. Measurement and simulation results are compared to prove the correctness of the structure. In addition, the lower and upper cutoff frequency are estimated by use of lumped-component circuit model and parallel plate waveguide model, respectively. Moreover, the IR-drop and DC resistance are examined through simulation in CST. And the quality of the signal transmission is analyzed based on eye pattern. The stopband, DC resistance and eye pattern of proposed structure are compared with those of traditional L-EBG structure. Compared with slotted L-EBG structure, the bandwidth of new structure is increased to 7.29 GHz and DC resistance decreases by 19.33 %. Meanwhile, MEO of the proposed structure improves 40 % higher than that of traditional L-EBG structure in terms of signal transmission quality.