I am currently looking at using the Hittite HMC636ST89 component and have done some thermal analysis at 85 degree C. Based on the simulation done it seems to show that the Channel Temperature of HMC636 on a bare PCB board exceeded the maximum channel temperature of 150 degree. Our channel temperature was derived as below
Channel Temperature = 5V*155mA(Typical supply)*75.6(Thermal Resistance) + 93.8 (Case Temperature from ANSYS) = 152.4 degree
As the above computation was derived using typical power drawn by the component with no other component on board I am worried that the component will have problem operating at +85 degreeC even though the stated operating temperature on the datasheet is -40 to +85 degreeC.
Based on my analysis above can anyone clarify if the HMC636ST89 component is suitable for use at +85degC?
Thanks and regards