Packaging & thermalMVP
Junction temperature
Steady-state junction temperature from dissipated power and thermal resistance.
Inputs
Result
Enter values and calculate to see the result.
Interpretation
Enter dissipated power, the package's junction-to-ambient thermal resistance, and the ambient temperature.
Formula
T_j = T_a + P · θ_JA
θ_JA = junction-to-ambient thermal resistance.
Variables
| Symbol | Variable | Unit |
|---|---|---|
| T_j | Junction temperature | K |
| T_a | Ambient temperature | K |
| P | Dissipated power | W |
| θ_JA | Thermal resistance | K/W |
Assumptions & validity
This tool assumes:
- Steady-state, one-dimensional heat flow (single θ_JA path).
- θ_JA is constant (independent of temperature and airflow).
- All dissipated power flows from junction to ambient through θ_JA.
Worked example
P = 5 W, θ_JA = 10 K/W, T_a = 25 °C.
ΔT = 5 × 10 = 50 K → T_j = 25 + 50 = 75 °C