Support for Thermal Models

Versal ACAP Packaging and Pinouts Architecture Manual (AM013)

Document ID
AM013
Release Date
2020-07-16
Revision
1.0 English

Xilinx offers and supports a suite of integrated device power analysis tools to help you quickly and accurately estimate your design power requirements.

The variability of design power requirements makes it difficult to apply pre-determined thermal solutions to fit all designs. The estimated power of the device using XPE, coupled with the your operating conditions and system constraints, dictate the appropriate solution. You must establish a thermal margin to account for the impact of the following (but not limited to) variations.

  • Impact of the thermal sensor accuracy
  • Impact of the power variation from one package to another package
  • Impact of the manufacturing variation between fans
  • Impact of the manufacturing variation between heat-sink fins
  • Impact of the package manufacturing variation between heat-sink flatness
  • Impact of the manufacturing variation of heat sink TIM contact/thickness

For example, when targeting maximum junction temperature (100°C) minus 8°C you must account for any additional system/environmental errors.

The detailed thermal model is a direct representation of the specified FCBGA package. The model provides geometric details describing the package, specifically in regards to the lid, TIM, die, underfill, substrate, and solder balls or leads. Each specific component in the detailed model has material properties associated. When using this detailed model, several key facts must be considered:

  • Two variations of the detailed thermal model are provided: Full detailed thermal model and simplified thermal model.
  • The full detailed thermal model provides all the intricate geometries representing the physical package and can be used for mechanical evaluation of the device. However, it should not be used to perform thermal simulations because the detailed geometries create a large meshing size and high-computation time with little to no increase in overall accuracy.
  • The simplified detailed model removes certain geometries including substrate trace layers and stiffener ring that do not have a material impact on thermal simulation accuracy and significantly increase computational time. This simplified model provides a much smaller meshing size and less computation time for simulation with less than a 5% difference in simulation accuracy from the full detailed model.
  • The correct package top surface contact must be used when modeling the TIM on top of the detailed model because the top surface contact might not be the actual full package size.
  • The junction temperature monitor point is at the die center by default. Junction temperature monitor points need to be positioned or added to the location of interest for your design.
  • The uniform power defined in the die for the models provided is default power and does not apply to any specific cases. Power setting input is required.