what about checking the datasheet of the mentioned regulators and see their normal temperatures ( with and without heatsink?!?)That way you will start getting used to reading a datasheet.
The AMS1117 series of adjustable and fixed regulators are easy touse and are protected against short circuit and thermal overloads.Thermal protection circuitry will shut-down the regulator shouldthe junction temperature exceed 165°C at the sense point.The power dissipation of the AMS1117 is equal to:PD = ( VIN - VOUT )( IOUT )Maximum junction temperature will be equal to:TJ = TA(MAX) + PD(Thermal Resistance (junction-to-ambient))Maximum junction temperature must not exceed 125°C.andThermal ResistanceControl Section -40°C to 125°C SO-8 package j JA= 160°C/WPower Transistor -40°C to 125°C TO-252 package j JA= 80°C/WStorage temperature - 65°C to +150°C SOT-223 package j JA= 90°C/W** With package soldering to copper area over backsideground plane or internal power plane j JA can vary from46°C/W to >90°C/W depending on mounting technique andthe size of the copper area.Thermal ConsiderationsThe AMS1117 series have internal power and thermal limitingcircuitry designed to protect the device under overload conditions.However maximum junction temperature ratings of 125°C shouldnot be exceeded under continuous normal load conditions.Careful consideration must be given to all sources of thermalresistance from junction to ambient. For the surface mountpackage SOT-223 additional heat sources mounted near the devicemust be considered. The heat dissipation capability of the PCboard and its copper traces is used as a heat sink for the device.The thermal resistance from the junction to the tab for theAMS1117 is 15°C/W. Thermal resistance from tab to ambient canbe as low as 30°C/W.
How hot is too hot?
It's upper limit is 125C
If the board runs on... say 5 volts. And you are putting in..... say 30 volts. The board is needing 2 amps to work.
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