The Research And Implementation Of The High Speed Serial Interface Circuit

Due to the design challenge taken by high frequency clock jitter and skew, parallel signal transmission cannot keep on increasing its frequency as the process advancing.Serial signal transmission is becoming the main data transmission mode in deep sub-micron meter process gradually. In China, we are still very poor in the research of the high speed serial signal transmission technology, so the research in this article mainly aims at the high speed serial transceiver circuit ,which is the key technology of the the high speed serial signal transmission system.Based on the deeply understanding of the theory of the high speed signal transmission, this article has designed and realized the CML and LVDS transceivers, which are used for PCI Express and can operate at the frequency of 1.25GHz. The layout of the two transceivers are fabricated in standard 0.13um CMOS process, the Hspice simulation results show that the two transceivers are well meet the desire of the data rate and other aspects of the PCI Express. During the course of designing LVDS and CML transceivers, this article also have solved some technical difficulties as below :1. A new LVDS receiver structure of pre-amplifier,current select module and main comparator has been put forward, which can increase the receiver sensitivity greatly.2. Optimize the common mode feed-back circuit, so that the LVDS driver can still have stable output common voltage at high operating frequency. Post simulation result shows that the difference between output common voltage and reference common voltage is not exceed 20mv.3. Optimize and realize a high precise band-gap reference voltage, its output will not change exceed 3mv with process,voltage,temperature change simultaneously.4. Pre-emphasis circuit modules have been designed CML driver, in CML receiver an equalizer circuit module has been used. Our simulation results show that these circuit modules have good effect of guarantting the quality of the high speed serial signal which has been transmitted across a long distance.