TheCircuitDogPower Design
LDO Power Dissipation Calculator
A quick screening tool to estimate heat in a linear regulator as it drops voltage at a specified output current.
Enter the values above and select Calculate result.
Formula
Ploss ≈ (Vin − Vout) × Iout; Tj ≈ Ta + Ploss × θJA
Worked example
A 5 V to 3.3 V LDO supplying 0.5 A dissipates approximately (5 − 3.3) × 0.5 = 0.85 W, before quiescent power.
Engineering notes
This calculation does not prove the regulator will start or survive. Check dropout, current limit, thermal data, package θJA and PCB copper in the actual datasheet.
Always compare calculated values with the actual component datasheet, tolerance stack-up, operating temperature and circuit conditions before applying them to hardware.