RF Amplifier Packaging and Thermal Dynamics
Packaging dimensions, weight, pinouts and material construction are critical features of any RF amplifier. These factors heavily weigh into the cost and feasibility of using a particular amplifier in a given design. Regardless of electrical and RF performance, if an amplifier can’t fit into the required footprint, the device won’t be serviceable for that application. It is also important to note that some RF amplifiers will require external components for optimal performance; these parts are often well defined in a specification sheet. But, these additional external components will increase cost and RF amplifier footprint. There are also many vibration, shock, dust, and ruggedness parameters that may be necessary to consider for applications requiring higher reliability devices.
Thermal dynamics are another element that must be considered when specifying an RF amplifier. The environmental factors and system factors can lead to very wide temperature ranges, as well as high peak temperatures. The maximum and recommended junction temperature of the transistors within an RF amplifier will be specified in a data sheet as a range of temperatures where the device can operate, or be stored without significant performance degradation.
Many of the performance characteristics will also be given over temperature, which must be maintained for desired performance. To ensure this, many specification sheets will also contain information on the proper landing pad design and methods to ensure proper thermal sinking.