🛑 While 65mW is fantastic for IEMs and standard consumer headphones, the standalone CX31993 lacks the raw current and voltage to properly drive hard-to-power equipment. High-impedance headphones (like 150Ω or 300Ω Beyerdynamics) or low-sensitivity planar magnetic headphones will sound thin, bass-shy, and flat.
To fix the heat issue, we must first look at how the CX31993 handles power. Why Does the CX31993 Run Hot?
The Conexant is a widely utilized high-fidelity USB-C DAC chip found in many "audiophile" dongles for its impressive 32-bit/384kHz sampling rate and >128dB SNR . However, users frequently report that these devices can run "hot" during extended use, particularly when driving high-impedance headphones or decoding DSD files. Why the CX31993 Runs Hot Heat in these ultra-compact dongles is typically caused by:
Check the box for "Allow the computer to turn off this device to save power." cx31993 datasheet fix hot
Inspect the 3.5mm jack. A partial short or high-impedance mismatch can cause the Class G amp to struggle and overheat.
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| Condition | Datasheet Spec | Defective Dongle | Fixed Dongle | | :--- | :--- | :--- | :--- | | Idle current (no playback) | <10 mA | 35-50 mA | 12-18 mA | | Load current (1kHz sine @ 0dB) | <80 mA | 150-200 mA | 85-95 mA | | Case temperature (30 min) | <45°C | 65-85°C | 41-48°C | 🛑 While 65mW is fantastic for IEMs and
Do this if VBUS > 4.2V. Remove any existing shunt resistor or cheap linear "regulator."
Similarly, users of the JCALLY JM7 reported: "It didn't heat up at all after testing for a long time; it's cold." . So, if you hold the casing and it feels physically painful to the touch, something is definitely wrong.
Software issues can often cause a dongle to pull more power than it should. Try these fixes in order: Why Does the CX31993 Run Hot
Check the datasheet schematic for the recommended decoupling capacitors on the VDD pins. Ensure you are using high-quality, low-ESR ceramic capacitors (MLCC) close to the power pins to eliminate voltage ripple that causes efficiency loss and extra heat.
Integrated Class G (dynamic power rail swapping) Native Power Output: ~1Vrms (approx. 50mW–65mW at 32Ω)
Identify the main square IC on the board.
First, identify whether the primary source of heat is the CX31993 chip itself or a secondary amplifier IC.