Signal Integrity Fundamentals Using ADS
应用文章
First, make sure which application you would like to use. Simulation skills between SERDES and DDR are quite different. In SERDES design, channel loss dominates system performance. Equalizers are used to compensate channel loss. In DDR design, delay, load and crosstalk are crucial. Timing analysis is essential for DDR analysis.
Second, there are two approaches to examine SI issues. By-Channel-Approach is for studying characteristics of channels such as loss, impedance mismatch and crosstalk. By-Signal-Analysis is for studying how the signal travels along the channel. We gauge signal quality with eye and eye statistics.
Third, Pre-layout Simulation is for defining PCB layout rules. Equation-based transmission line components are generally used as channel models. Post-layout Simulation is for examining the performance of real PCB routing. EM solvers are used to extract channel models from a PCB layout.
Finally, you have to understand the capabilities of the three simulators. S-parameters simulator is used to calculate channel performance in frequency domain. Transient is used to simulate the time domain waveform of a link including transmitter, channel and receiver. ChannelSim is used to calculate the statistics of eye pattern and the eye statistics of a link.