Thermal Management

This topic provides guidelines for heatsink and airflow solutions to ensure the Orca M.2 module operates within safe thermal limits.

Thermal Management Overview

The Orca M.2 module includes internal temperature monitoring and a frequency throttling mechanism to prevent overheating. To maintain optimal performance and prevent thermal throttling during intensive workloads, effective thermal management is crucial. If the module exceeds a preset high-temperature threshold, the firmware automatically reduces the operating frequency until the temperature returns to safe levels. This helps avoid damage due to insufficient heat dissipation.

For environments with high ambient temperatures or extended workloads, additional cooling solutions, such as heatsink and airflow, may be required to maintain optimal operating temperatures.

Heatsink and Airflow Requirements

Thermal dissipation can be approximated by the following the formula:

$$\text{Ambient Temperature} + W \times R_{TJA} < \text{Maximum Operating Temperature}$$

Where:

• \text{W}\: Power Dissipated by the Orca module (Watts)

• $R_{TJA}$: Thermal resistance from junction to ambient (°C/W)

• $\text{Maximum Operating Temperature}$: Junction temperature limit

The total thermal resistance of $R_{\text{TJA}}$ consists of:

• $R_{JC}$: Junction-to-case thermal resistance (0.3 °C/W)

• $R_{CHS}$: Case-to-heatsink thermal resistance (0.12 °C/W with thermal paste or pad)

• $R_{HSA}$: Heatsink-to-ambient thermal resistance

Example Calculation

Consider a scenario where the Orca module dissipates 3 W, the ambient temperature is 70 °C, and the recommended maximum operating temperature is 95 °C.

70\,^\circ\text{C} + 3\,\text{W} \times \left(0.3\,^\circ\text{C/W} + 0.12\,^\circ\text{C/W} + R_{HSA}\right) < 95\,^\circ\text{C}

Solving for $R_{HSA}$:

R_{HSA} < 5.4\,^\circ\text{C/W}

A heatsink with thermal resistance lower than 5.4 °C/W is required to maintain safe operating temperatures. The user should select an appropriate combination of heatsink type, size, and airflow to ensure a thermal resistance of less than 5.4 °C/W for this example.

Heatsink and Airflow Design Guidelines

• Material: Use aluminum or copper for optimal thermal conductivity.

• Dimensions: Ensure the heatsink is appropriately sized for the M.2 2280 form factor (22 mm x 80 mm).

• Attachment: Use thermal pads or thermal paste to enhance heat transfer between the module and heatsink.

  • Airflow:

    • In environments with limited airflow, a passive heatsink may be sufficient.

    • For more demanding applications, active cooling solutions (e.g., small fans or improved ventilation) are recommended. Optimize airflow direction and placement for maximum cooling efficiency.

Example M.2 2280 Heatsinks

M.2 2280 heatsink with an active cooling fan

M.2 2280 passive heatsink

M.2 2280 passive heatsink with visible heat pipes

Example heatsink installations

Testing and validation

• Thermal Testing: Monitor the module’s temperature under typical workloads to validate the cooling solution.

• Frequency Throttling: Observe any signs of frequency throttling, which may indicate inadequate cooling.

• Long-Term Reliability: Keep the module within recommended temperature limits to prevent degradation and ensure stable, high-performance AI inference during extended or heavy workloads.