Electronics Engineering

Forced-Air PCB IC Package Junction-to-Ambient Thermal Resistance Estimator Calculator

Forced-Air PCB IC Package Junction-to-Ambient Thermal Resistance Estimator engineering calculator.

Quick Answer

Calculate Forced-Air PCB IC Package Junction-to-Ambient Thermal Resistance Estimator

Calculator

Junction-to-ambient thermal resistance (K⁄W)
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Result Interpretation

Forced-Air PCB IC Package Junction-to-Ambient Thermal Resistance Estimator Calculator computes Junction-to-ambient thermal resistance in K/W using the defined engineering formula and the input values provided.

Worked Example

Verified calculation

Given:

  • Package junction-to-case thermal resistance = 3.5
  • Effective heat-dissipating surface area = 0.0004
  • PCB conductive thermal resistance from package to ambient reference plane = 12
  • Forced convection heat transfer coefficient = 25

Expected Result:

  • Junction-to-ambient thermal resistance = 115.5

Engineering Interpretation:

Under the given input conditions, the calculated result is: Junction-to-ambient thermal resistance = 115.5 K/W.

The actual numerical result is computed by the Runtime engine using the persisted tool definition. The values shown here come from automatically validated test cases.

Formula / Method

junction-to-ambient thermal resistance = (1.0 / (forced convection heat transfer coefficient * effective heat-dissipating surface area)) + pcb conductive thermal resistance from package to ambient reference plane + package junction-to-case thermal resistance

Formula family: formula_electronics_ic_package_thermal_resistance_thja_estimator_for_forced_air_cooled_pcbs

Variables

SymbolLabelRoleDescription
h_forced Forced convection heat transfer coefficient INPUT Forced convection heat transfer coefficient
A_eff Effective heat-dissipating surface area INPUT Effective heat-dissipating surface area
R_board PCB conductive thermal resistance from package to ambient reference plane INPUT PCB conductive thermal resistance from package to ambient reference plane
R_jc Package junction-to-case thermal resistance INPUT Package junction-to-case thermal resistance
theta_ja Junction-to-ambient thermal resistance OUTPUT Junction-to-ambient thermal resistance

Calculation Steps

  1. Enter the forced convection heat transfer coefficient in W/(m^2*K).
  2. Enter the effective heat-dissipating surface area in m^2.
  3. Enter the pcb conductive thermal resistance from package to ambient reference plane in K/W.
  4. Enter the package junction-to-case thermal resistance in K/W.
  5. Step 1: Compute junction-to-ambient thermal resistance.
  6. Read the junction-to-ambient thermal resistance (K/W) from the results.

Engineering Summary

Calculate Forced-Air PCB IC Package Junction-to-Ambient Thermal Resistance Estimator

Frequently Asked Questions

What does this calculator calculate?

The Forced-Air PCB IC Package Junction-to-Ambient Thermal Resistance Estimator Calculator estimates Junction-to-ambient thermal resistance based on the input parameters you provide

Why is forced convection heat transfer coefficient important in this calculation?

forced convection heat transfer coefficient is directly proportional to junction-to-ambient thermal resistance. When you enter forced convection heat transfer coefficient in W/(m^2*K), the calculator uses it in the engineering formula to compute the output

How should I interpret the result junction-to-ambient thermal resistance?

The calculator outputs junction-to-ambient thermal resistance in K/W. The result is computed directly from the input values using the defined engineering formula

What units should I use for the inputs?

Enter each value in the units shown next to the input field: Forced convection heat transfer coefficient (W/(m^2*K)), Effective heat-dissipating surface area (m^2), PCB conductive thermal resistance from package to ambient reference plane (K/W), Package junction-to-case thermal resistance (K/W). Make sure all inputs use the specified units for consistent results

What assumptions does this calculator use?

This calculator uses automatically validated engineering formulas. Results are approximate and should be validated against site-specific conditions, applicable codes, and professional engineering judgment

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