TMS320DM365 Video Circuit Board Design And Signal Integrity Analysis

As the integrated circuit technology and electronic design technology develop continuously, the signal integrity for the high-speed digital circuit has been an unavoidable problem for electronics engineers. Only mastering related theories and technologies for high-speed circuit, adopting design method of simulated analysis and guiding PCB design by constraint rules of locating and wiring, they can successfully design a piece of circuit board. This paper will take PCB design for dm365 as an example, discuss board level simulation and design realization process of an integral high-speed PCB, run signal integrality design concept through the overall PCB design, transform the simulation results into constraint rule to guide PCB design for the dm365, simulate PCB after wiring, and finally conduct test and verification for the mainboard to complete PCB design function of the dm365.This paper mainly analyzes the signal integrity problem that has to be faced in the process of designing dm365 circuit board, including the reflection analysis of each memory bus, by which the impedance matching strategy is obtained. For the crosstalk problem, the effects of coupling length and spacing on crosstalk are discussed, finding the wiring method for restraining crosstalk. With regard to the timing problem of memory bus, the timing relation formula that is mandatory in memory module is derived, and the timing simulation after wiring is carried out to verify whether the circuit board wiring meets the timing relation formula, so as to guide the wiring in memory module. The design method of power distribution network is analyzed, the method of improving target impedance is proposed, and based on this method, the power distribution network is designed, so as to provide guidance for the model selection and placement of decoupling capacitor and reduce the synchronous switching noise. A harmonic analysis is made for the power plane of the whole circuit board, guiding the layout design of circuit board.In addition, this paper also detailed the circuit schematic design of main function modules of video circuit board, including memory DDR2 module, video TVP5146m2 module, and power module. And based on this, the PCB packaging design, stacking design, and locating and wiring are made, and the circuit board is improved on the basis of simulation.