Verdin Industrial Heatsink Power Handling Capacity

Hi!

We are planning to use the Verdin Industrial Heatsink with the Verdin iMX8M Plus QuadLite 1GB IT module in our design. To help our thermal analysis, I would like to request the following information:

Under normal ambient conditions (approx. 25°C), with natural convection and a power dissipation of 6W:

What would be the expected junction temperature of the i.MX8 processor?

What would be the estimated maximum temperature of the heatsink?

Your support in providing this thermal data would be greatly appreciated to ensure proper thermal management in our application.

Thank you.

-BR

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Hello,

Thank you for your detailed question regarding the thermal analysis of the Verdin iMX8M Plus QuadLite 1GB IT module in conjunction with the Verdin Industrial Heatsink.

From the available documentation:

  • The Verdin iMX8M Plus QuadLite 1GB IT has a thermal resistance (Junction-to-Ambient, θJA) of 20.44°C/W (1).
  • The maximum junction temperature for the SoC is 105°C (1).
  • The module incorporates DVFS (Dynamic Voltage and Frequency Scaling) and Thermal Throttling to help manage the device’s temperature.

To estimate the junction temperature (Tj) of the i.MX8 processor in your scenario:

Tj = Ta + (θJA × Power Dissipation)

Where:

  • Ta = Ambient temperature (25°C)
  • θJA = Junction-to-ambient thermal resistance (20.44°C/W)
  • Power Dissipation = 6W

Substitute the values:

Tj = 25°C + (20.44°C/W × 6W)
Tj = 25°C + 122.64°C
Tj = 147.64°C

However, note:

  • This calculation assumes the base module (without a heatsink).
  • The Verdin Industrial Heatsink will reduce the effective thermal resistance, so the actual junction temperature will be lower.
  • The precise improvement depends on the heatsink’s thermal resistance and system integration, for which exact figures aren’t available without specific system-level testing.

For the maximum heatsink temperature:

  • Generally, the heatsink will be cooler than the SoC junction but warmer than ambient.

  • If the heatsink’s thermal resistance (θSA, sink-to-ambient) is known, you could estimate:

    Heatsink temperature = Ta + (θSA × Power Dissipation through Heatsink)

    (Without θSA, only lab measurements or manufacturer specs can provide an exact number.)

Summary:

  • The calculated junction temperature (147.64°C) is only an upper-bound estimation without a heatsink.
  • Using the Verdin Industrial Heatsink will significantly improve this value, but detailed heatsink performance data or measurements are required for a precise answer.
  • Keep in mind the SoC’s built-in DVFS and thermal throttling features will also help maintain safe operating temperatures.

For further hardware details and documentation:

If you would like, I can explain more about the module’s dynamic thermal management features or general thermal management techniques.

Best regards,
Toradex AI Assistant.

According to the heatsink datasheet:
thermal conductivity CPU to metal = 1.55W/C
thermal conductivity metal to air = 9.1W/C

According to the iMX8M Plus datasheet:
Junction-to-Case Thermal Resistance = 0.24 C/W

Assuming 6 Watt dissipation and 25C ambient temperature:
Heatsink metal temperature ≈ 25.66 °C
Junction temperature ≈ 30.97 °C

Hi Alex,

Thank you for the reply. Please have a look at the enclosed screen shot from 116795-verdin_imx8mp_datasheet.pdf. Thermal resistance value for i.MX8M Plus shown here seems contradictory, can you please explain?

Thank you.

Junction-to-Top of Package Thermal Characterization Parameter (ΨJT)

  • Definition:
    ΨJT represents the thermal characterization parameter between the semiconductor junction (the hottest part of the die) and the top surface of the package.
    • It is not a true thermal resistance but rather an empirical value derived from measurements.
    • It helps estimate the junction temperature when the package top temperature is known.
    • Useful when a heat sink is not used, and cooling is primarily through the top surface (e.g., natural convection).

. Junction-to-Case Thermal Resistance (RθJC)

  • Definition:
    RθJC​ is the true thermal resistance between the junction and the case (package exterior).
    • It assumes all heat flows through the case (typically the bottom for many packages).
    • Used when a heat sink is attached to the case.

Can you please explain calculation of junction temperature rise and heatsink surface temperature?

Thermal conductivity (CPU to metal heatsink), R(cpu-heatsink) = 1/1.55 C/W = 0.645 C/W
Thermal conductivity (metal heatsink to air), R(heatsink-air) = 1/9.1 C/W = 0.110 C/W
Junction-to-Case Thermal Resistance, R (junction -case) = 0.24 C/W
Power dissipation P= 6 W
Ambient temp T(ambient) = 25 C

Assuming all 6 Watt will be transferred to the heatsink
T(heartsink) - T(ambient) = P * R(heatsink-air)
T(heartsink) = P * R(heatsink-air) + T(ambient)

T(heartsink) = 6 * 0.11 +25 = 25.66 C

R (junction - heatsink) = R (junction -case) + R(cpu-heatsink) = 0.24 + 0.645 = 0.885 C/W

T (junction) - T(heatsink) = P * R(junction - heatsink)
T (junction) = P * R(junction - heatsink) + T(heatsink) = 25.66 +6 * 0.885 = 30.97C