DC Electrical (DC-IR) -> CFD Thermal (IcePak) -> AC Simulation (SIWave): Natural Convection
The main source of heat which elevates this board above the ambient temperature of the case is the heat
dissipation from each of the DRAM chips, and the resistive losses in the copper board. SIWave can easily
simulate this DC operation condition, simply by assigning a voltage source to the pin on the connector which
supplies the voltage, and assigning current sinks to all of the devices which will draw current. This was done for
our board, and then the DC-IR simulation performed, giving the following distribution of current:
Next up is to take these heat flow sources, and simulate how they would spread throughout the board and
throughout the air surrounding using an IcePak CFD + Thermal simulation. In this simulation, air is allowed to
flow freely and bring heat away from the board through natural convection. Below are the surface temperature
results of the board after simulation in these conditions:
Now, we will include this temperature map in our SYZ simulation we use to extract the channel S-parameters
necessary to plots our eye diagrams. This is done through the material editor in the stackup dialogue, in which
one can add a thermal modifier. Our stackup is comprised of copper conductor and FR-4 dielectric, which vary
with temperature as given below: