|
Original Date: 11/01/2004
Revision Date: 01/18/2007
Best Practice : Design for Harsh Environments: Low-Temperature Operation
The Center for Advanced Life-Cycle Engineering has developed assessment methodologies and performance characterization expertise for electronic components in low-temperature application environments. This expertise assists systems designers and manufacturers in developing cost-effective systems that function in these environments.
Until recently, low-temperature applications for electronic components were addressed using selective heating pads in printed circuit boards (PCBs) or extensive experimentation and testing to select the best materials and design parameters. This method was used primarily because of the lack of data on performance and reliability at low temperatures and the lack of parts rated for low temperatures.
Using a physics-of-failure (PoF) approach, the Center for Advanced Life-Cycle Engineering (CALCE) developed a methodology for characterization of device performance, materials behavior, and package failure modes at low temperatures. The methodology has been used on telecommunication infrastructure equipment application, where the parts were divided into major technology categories and information from the manufacturers was obtained. Examples of the property trends for package materials at -70°C include increases in Young’s modulus, yield strength, thermal conductivity of some materials, decreases in specific heat, co-efficient of thermal expansion, and thermal conductivity of metal alloys. The categories of the devices were then analyzed and characterized, allowing for reduction in the need for selective heating pads. This could potentially result in cost savings of approximately 10% per PCB assembly where the pads could be eliminated.
The methodology has also been used in a Mars application where the wire span and loop height were optimized for Chip-on-Board technology using analytical model. The results from the model were verified by experiments conducted at the Jet Propulsion Laboratory and Applied Physics Laboratory. This approach can potentially save more than $200K in test resources per year, per mission.
For more information see the
Point of Contact for this survey.
|
