PROMs can be thought of as active-at-power-up devices. The dynamic power associated with these devices spans microseconds (over FPGA configuration time) and the static power consumption of PROM devices is very low (owing both to technology node and density). So, in the typical case, PROMs do not contribute much to the power / thermal challenges. Hence, in the board level thermal model, representing the PROM is absolutely not critical.Owing to this reason, at this time, package thermal models for PROM devices are not provided by Xilinx.