Before we fix the heat, we must determine if your unit is faulty or functioning within spec.
It is normal for high-performance portable DACs to generate heat because they draw significant power (often pulling
The CX31993 is a remarkably capable chip when treated correctly. Overheating is not a feature; it is a sign of cost-cutting by manufacturers who ignore the datasheet's power, layout, and termination requirements. By applying the fixes above—adding a proper LDO, Zobel networks, and thermal vias—you can transform a burning-hot dongle into a cool, high-fidelity audio interface that meets or exceeds its specifications.
Issue: PLL staying active.
has emerged as one of the most popular, cost-effective USB-C DAC (Digital-to-Analog Converter) chips for mobile audiophiles. Offering 32-bit/384kHz sampling rates, high SNR (>128dB), and a robust 65mW output, it packs impressive performance into a tiny package. However, this high performance often comes with a significant drawback:
The (often branded by Conexant or Synaptics) is a popular budget USB-C DAC chip known for high-resolution audio (32-bit/384kHz) but frequently lacks an official, public datasheet. Users often report "hot" operating temperatures or overheating, especially when paired with an external amplifier like the MAX97220 .
Remember the inefficient voltage regulator? Replace the stock 3.3V LDO with a (ultra-low dropout, 90% efficient). This requires SMD soldering but eliminates the primary heat source. cx31993 datasheet fix hot
Budget designs may lack proper heat dissipation (heatsinks or thermal pads), causing the zinc alloy or plastic shells to become hot to the touch during extended use.
With headphones connected, play a 1kHz sine wave at 50% volume. Use an oscilloscope probe on L_OUT (pin 18). Look for high-frequency ripple (>1MHz) riding on the signal. If present → oscillation.
This information is for educational purposes only. Modifying your hardware may void its warranty. The author is not responsible for any damage resulting from the application of these techniques. Before we fix the heat, we must determine
Wrap the PCB layer tightly with a layer of polyimide (Kapton) tape for electrical insulation, followed by copper foil tape to act as a heat spreader.
Before fixing anything, we must understand the chip's intended electrical behavior. The official CX31993 datasheet (Rev 2.1, typically) specifies several critical parameters:
The has established itself as one of the most popular budget digital-to-analog converter (DAC) chipsets on the audiophile market. Celebrated for its ability to deliver premium ultra-high-resolution audio—boasting up to 32-bit/384kHz PCM decoding and a 128dB signal-to-noise ratio (SNR) —it powers countless ultra-portable "dongle" DACs. By applying the fixes above—adding a proper LDO,
If your CX31993 dongle is burning your desk mat, run this diagnostic flow: