Turn up the Heat: An Electrical-Thermal MMIC Design Flow
Electronic circuit design typically begins with an assumption that the components are operating at ambient temperature. Monolithic Microwave Integrated Circuit (MMIC) design, in particular, violates this as the DC current flowing through the ever-shrinking devices induces heating to two, three, or even four times greater temperature (in ºC). Such a large departure from assumed room temperature behavior impacts phase, gain, efficiency, noise, and intermodulation distortion. Circuit designers need tools with integrated electrical-thermal analysis to address these performance issues.
With the continual increase in power densities for radar and mobile communication applications, device reliability is also a design concern. Product life cycle for base station and fixed wireless applications is much longer than terminals, so field failures are costly. Highly reliable devices able to maintain performance over prescribed useful lifetimes are required. Furthermore, outdoor installation of base stations mounted in equatorial regions may require components to sustain operation at 85 °C case temperatures. To ensure continuous operation, component reliability mean-time to failure (MTTF) values in excess of 106 hours are typically called for.