After you know the contact area for the device, you can think about the design of the heatsink base. Decisions made here can significantly impact the area, performance, and cost of the thermal solution and should not be overlooked. One consideration that can have significant impact on the base design is how many devices the heatsink must cool. Having a heatsink dedicated to a single device allows sizing and height tolerances to be optimized for that device often leading to both easier design and higher performance. On the other hand, a single heatsink that must touch multiple devices often must have compromises in size and height tolerance optimization that leads to less than ideal results. There are ways to compensate for this. However, for the basis of this application note, AMD assumes the heatsink is dedicated to the AMD device or in cases that it is not, the AMD device is the most thermally critical, and thus the heatsink is optimized towards the AMD device.
Tip: System level thermal design is part of the
normal engineering process when developing a product. AMD
recommends thermal simulation to evaluate and optimize thermal performance. While not
all customers have access to these simulators or the expertise for thermal simulation,
AMD has thermal partners available to help. Reach out
to the thermal partners directly if assistance is
needed.