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Series 242 DMD Temperature Limit

Colin Roach
Prodigy 20 points

Hi all,

I apologize if this is the incorrect forum, but I can't find one specific to questions about DMD components.

My question is regarding the 0.3 WVGA EM DDR Series 242 DMD.

The absolute maximum temperature rating is listed as 75C for BOTH a reference location (TC1) on the ceramic package AND the active array. How is this possible? According to the datasheet, the active array temperature must be calculated as a sum of TC1 and some power produced by the array. Clearly, the active array temperature will always be hotter.

So, is this maximum temperature of 75C referring to the active array, in which case I have to back out a cooler TC1 based on operating conditions? Or does it mean that the active array can be some value hotter than TC1, when TC1 is 75C?

Thanks!

Colin

  • 0
    TI__Intellectual 2200 points

    Hi Colin,

    You are correct, the array will always be hotter than the ceramic during operation.  Both are limited to 75ºC max which means that the array will be the limiter.  We added the 75ºC spec to the ceramic to somewhat protect us from people who claim they didn’t know they needed to calculate the array temperature or disagreed with the calculation equations.  Please to calculate the array temperature using the equations provided in the datasheet and to recognize that the absolute max temperature of the array is 75ºC.

    Regards,

     

    Frank Xu

  • 0 in reply to Frank Xu
    Prodigy 20 points

    Excellent. Thank you for the clarification, Frank.

    I'll just make sure that T_array in the equation is 75C, and then back out the ceramic temperature. With this maximum ceramic temperature I can then calculate the maximum inlet air temperature allowed (forced convection) for the DMD not to overheat.