Max Junction Temperature
Use this calculator to find the maximum junction temperature of the device from power dissipated thermal resistance of device junction to case and junction to air.
Result
Max junction Temperature
oC
TJ - Junction temperature
P - Power dissipated
RTH - Thermal resistance of device junction to air
Ta - Ambient Temprature
Junction temperature, short for transistor junction temperature, is the highest operating temperature of the actual semiconductor in an electronic device. In operation, it is higher than the case temperature and the temperature of the part's exterior.
Thermal Resistance for PCB Copper
| Heat Sink | Thermal resistance (°C/Watt) |
| 1 sq inch of 1 ounce PCB copper | 43 |
| .5 sq inch of 1 ounce PCB copper | 50 |
| .3 sq inch of 1 ounce PCB copper | 56 |
| Aavid Thermalloy, SMT heat sink: PN:573400D00010 | 14 |
Thermal Resistance for Various Electronics Packages
| Package | Junction to Case (°C/Watt) | Junction to Air (°C/Watt) |
| TO-3 | 5 | 60 |
| TO-39 | 12 | 140 |
| TO-220 | 3 | 62.5 |
| TO-220FB | 3 | 50 |
| TO-223 | 30.6 | 53 |
| TO-252 | 5 | 92 |
| TO-263 | 23.5 | 50 |
| D2PAK | 4 | 35 |
