AnsweredAssumed Answered

HMC636ST89 Operating Temperature

Question asked by KYM on Jul 27, 2015
Latest reply on Aug 25, 2015 by kkaya



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

Yee Mong