Contained is a review of a conductive heat approach to specify the maximum input or dissipated power of a Pi Attenuator at any arbitrary dB value. Challenges arise from the fact that Pi Attenuators are made from 3 resistor element networks where some fraction of input power is converted to heat by each resistor, and then dissipated by the system. As the dB value changes, so too does the value of these resistors. This, in turn, affects what fraction of the input power to be dissipated as heat will be. For this reason, two attenuator pads of different dB values will have different power ratings even though their landing footprint is identical. Their size being equal it may then follow that a 1dB Pad has a higher Input Power Rating than a 10dB Pad since the 1dB requires less power to be dissipated than the 10dB.
In the course of this discussion we will explore the relationships of Resistor Film Temperature, Resistor size, Resistor Trim Depth, Thermal Conductivity, Component thickness, and Ground/Sink Operating Temperature all influence what Power Rating an Attenuator may be reasonably expected to handle.
