Second-Sourcing a Semi-Custom Module Two Years Later
Second-sourcing a semi-custom module two years post-launch demands complete native CAD source files, uncompiled firmware, and validated factory test jigs.
Thermal Aging
Meaning
Stress tests accelerate the degradation of electronic components by exposing them to high temperatures over extended periods. Thermal aging allows engineers to predict how a product will behave after several years of use in a matter of weeks. This process identifies potential failure points in the solder joints, the battery chemistry, and the plastic enclosures before the device is released to the market.
Material Degradation
Heat causes physical changes in the structure of the metals and polymers used in construction. In the context of thermal aging, the diffusion of atoms can create brittle intermetallic layers at the interface between the component and the circuit board. These layers are prone to cracking when the device is later subjected to mechanical shocks or vibration.
Reliability Testing
Samples are placed in environmental chambers where the temperature is held at a constant high level or cycled between extremes. Scientists monitor the performance of the electronics throughout the thermal aging cycle to record any shifts in electrical parameters. A significant change in the resistance of a connection or the capacity of a capacitor indicates a potential reliability risk.
Life Expectancy
Mathematical models translate the results of the accelerated test into a real world duration. By observing the failure rate during thermal aging, the manufacturer can determine the expected warranty period and the necessary cooling requirements for the product. This data ensures that the device can survive the harsh conditions it might encounter during its operational life.