How Jetson Nano Cooling Works: Fans, Heatsinks & Airflow

1. The Heat Path: Chip to Heatsink to Air

The CPU, GPU and other circuitry generate heat during operation. Good contact between the processor assembly and heatsink provides a conduction path. A thermal interface material helps bridge small surface gaps; uneven contact can limit cooling even when the fan runs quickly.

The metal heatsink spreads heat into its fins, increasing the surface area exposed to air. With passive cooling, natural convection moves warmed air away. Active cooling uses a fan to drive more air across the surfaces. The heatsink and fan perform different jobs, so both must suit the installation.

2. What the Cooling Fan Actually Does

An axial fan’s motor turns an impeller. Its blades create a pressure difference that moves air through the cooling assembly. Replacing warm air around the fins with cooler incoming air improves convective heat transfer. The fan does not remove the need for a heatsink or a clear inlet and outlet.

Check the airflow-direction arrow on the selected fan. A fan mounted above a heatsink may blow toward the fins or draw air through them, depending on the assembly. The better arrangement depends on fin geometry, clearances and enclosure openings. Confirm it with temperature measurements in the finished equipment.

3. Why CFM Alone Does Not Determine Cooling

Free-air airflow is measured with little resistance. Heatsink fins, guards, dust filters and narrow vents all restrict flow. The installed airflow occurs where the fan’s pressure–airflow curve meets the system’s resistance curve. A higher free-air CFM value does not automatically mean a lower processor temperature.

Keep the fan inlet clear, provide a path through the fins, and prevent hot outlet air from returning directly to the inlet. An open development board and the same board inside a compact case can have very different cooling requirements. See our fan P–Q curve guide for the operating-point explanation.

4. PWM Control, Speed Feedback and Thermal Protection

NVIDIA documents fan-speed control and clock throttling as parts of Jetson Nano thermal management. Fan control can increase cooling demand as temperature rises; throttling reduces clock frequency when thermal limits require it. This can affect sustained workload performance. Follow the documentation for your installed Jetson Linux release. NVIDIA thermal-management reference.

PWM is a speed-control input. FG, also called tachometer output, reports fan rotation to compatible monitoring hardware. RD is a fault-status option on some fans; it is not interchangeable with an FG signal.

For the Jetson Nano 2GB Developer Kit, NVIDIA specifies a 5 V fan header with PWM and tachometer connections; some early variants do not have that header fitted. Board revisions and other Jetson families differ. Check the board guide, supply-current limit, connector and pinout before connecting a replacement fan. NVIDIA developer-kit guide.

5. A 40 mm Fan Selection Example: JyFan JF4010

The supplied JF4010 datasheet describes a 40 × 40 × 10.4 mm DC axial fan, with 5 V and 12 V versions and optional FG, RD and PWM functions. It is a reference for compact AI equipment selection, not a verified drop-in replacement for a specific Jetson board. Only consider the appropriate supply-voltage version for the intended connection.

Maximum airflow and maximum static pressure are separate endpoints. These fan ratings are not Jetson temperature-test results. The PDF specifies a 10.4 mm depth; check the mechanical drawing rather than assuming an exact 10 mm installation envelope.

6. Validate Cooling in the Final Enclosure

• Match the mechanics: Verify mounting-hole centers, screw engagement, fan depth and clearance above the inlet.
• Match the interface: Confirm voltage, starting current, connector pinout, PWM requirements and any speed-feedback signal.
• Use a representative workload: Run the intended AI, vision or robotics task in the intended power mode until temperatures stabilize.
• Measure the complete system: Record ambient temperature, module temperature, fan speed, noise and any throttling with the enclosure assembled.
• Check the operating environment: Consider elevated ambient temperature, dust buildup and blocked vents when defining the maintenance interval.

Sources & Selection Resources

• NVIDIA: Jetson Nano 2GB Developer Kit User Guide
• NVIDIA: Jetson Nano and Jetson TX1 Power and Thermal Management
• JyFan JF4010 Datasheet, Rev. 1.0 — supplied for this article

Jetson Nano and Jetson Orin Nano are different platforms. This article does not establish compatibility across Jetson families. NVIDIA and Jetson are trademarks of NVIDIA; no endorsement or partnership is implied.