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UA78: UA78M12C thermal overload protection

Part Number: UA78

Dear  TI ‘s engineer,

          there is a customer ask for a question about that how much is the temperature of UA78M12C thermal overload protection? from the datasheet just show the device has internal thermal overload protection,and the operating virtual junction temperature is 150℃,if it is the thermal overload protection temperature?

  • Hi,

    The purpose of thermal overload protection is to maintain the average device junction temperature at the absolute maximum rating of 150 C. Keep in mind that the maximum recommended junction temperature for the UA78 is 125 C. Operating outside of the recommended conditions (0 C to 125 C) can degrade performance and reliability. The maximum recommended power dissipation can then be approximated with the following equation:

    Pd,max = (Tj,max - Ta) / Rja

    Where Tj,max = 125 C, Ta is the ambient operating temperature, and Rja is the junction-to-ambient thermal resistance.

    Thanks,
    Gerard
  • Dear Gerard,

    Thanks very much,get it,and i will feedback to our customer as your describe。