Engineering Tech III
Product Development Engineer
News Bits and Pieces -
September 22, 2005
Texas Instruments (TI) engineers helped a disk drive manufacturer get their product to market six months early by using thermal simulation to solve problems prior to the prototyping phase. The potential thermal problems centered on a disk brake integrated circuit (IC) that consumed 9 watts. The challenge was optimizing the package design to move this heat out to the PCB and then moving as much as possible of this heat to the chassis. “Using traditional build-and-test methods it would have probably taken a year to identify a design that maintained junction temperatures at or below specifications,” said Frank Mortan, Packaging Engineer for TI. “Instead, long before the prototype stage, we began simulating alternative printed circuit board approaches and so we were able to optimize the design from a thermal standpoint in only six months.”
TI’s approach to assisting customers with thermal design relies heavily on the use of thermal simulation to evaluate a wide range of alternative configurations in software without the need for prototype parts. In this case, the customer got TI involved in the project early and TI recognized the potential for a problem and offered its services in helping to resolve it. Mortan and Sandra Horton, also a TI Packaging Engineer, modeled the customer’s product using the Flotherm thermal simulation environment from Flomerics. They used the “Flopack” web site (www.flopack.com) to create a detailed thermal model of the IC die, package and the PCB. Instead of creating the geometry manually, all they had to do was enter simple parameters defining each component and the web site generated the model components automatically, allowing a detailed system model to be built within Flotherm. “This approach made it possible in the space of a single day to model a complex electronic system to a high level of accuracy and predict cooling performance,” said Mortan.
After running a large number of iterations over a period of several months, Mortan and Horton were confident they had optimized the design. They ordered physical prototypes built and found that, as predicted by the simulation, their design was well within thermal specifications. The measured die temperature was 121 degrees C while the model predicted 125 degrees C for the bulk silicon. So the model was off by just 4 degrees C, or 3.2%. “When we showed our results to the customer they were very pleased,” said Mortan. “They were happy that we were able to resolve potential thermal concerns up front while the electronic design was being completed rather than discovering them during the prototyping phase. I don’t think there’s any doubt but that the product reached market six months early because thermal simulation solved the problems prior to the prototyping phase.” www.flomerics.com
The Virginia Engineer © IIr Associates 2005