The PCB macro in Ansys Icepak allows you to create block and plate objects with orthotropic conductivities that can be used to model a printed circuit board (PCB). Note that the PCB macro is different from the PCB object that you can create by clicking on the   button in the Object creation toolbar (see Printed Circuit Boards (PCBs)). The PCB object is used to create a specified number of boards in a rack. The PCB macro creates a solid block object as well as conducting plate objects (if specified) with orthotropic conductivities that model just one printed circuit board.

To configure a PCB macro in your model, you must specify the position and thickness of the board, the number of copper layers, and the thickness of each copper layer.

Ansys Icepak creates a custom material to represent the properties of the PCB. (See Material Properties for details on materials.) This material has different thermal conductivities parallel to and normal to the plane of the board (k_parallel and k_normal , respectively). Ansys Icepak calculates the two thermal conductivities based on your inputs and creates the custom material. The thermal conductivities are calculated using the following equations:

(33–1)

(33–2)

where k_cu is the conductivity of the copper in the PCB (Ansys Icepak always uses a value of 400 W/m-K for this macro), k_subs is the conductivity of the substrate in the PCB (Ansys Icepak always uses a value of 0.2 W/m-K for this macro), h_pcb is the thickness of the PCB, and h_cu is the total thickness of copper in the PCB. Ansys Icepak calculates h_cu using

(33–3)