The CX31993 can deliver amazing 32bit/384kHz audio without burning your desk – but only if you respect the thermal laws hidden in its elusive datasheet.
If using USB Audio Player Pro , increasing the USB Buffer Size and toggling Bit-Perfect mode can sometimes stabilize the power draw and reduce crackling/static associated with heat.
is a high-performance USB-C DAC chip from Conexant, widely used in budget "Hi-Fi" dongles. While it offers impressive specs like 32-bit/384kHz sampling and >128dB SNR, users frequently report issues with the device becoming physically hot during use, particularly when paired with Windows systems or high-resolution formats like DSD. 1. Core Specifications cx31993 datasheet fix hot
The Conexant CX31993 has become ubiquitous as a budget-friendly USB-C to 3.5mm DAC dongle. Its subjective reputation, however, is polarized: many praise its detail retrieval, while others complain it sounds “hot,” “glassy,” or “fatiguing.” This harshness is not a flaw in the core DAC architecture—it is a predictable consequence of and missing post-DAC filtering , as hinted at in the component’s reference design.
Finding a detailed official datasheet for the Cx31993 can be difficult as it is a legacy chip (often associated with manufacturers like Chroma or similar OEMs). The CX31993 can deliver amazing 32bit/384kHz audio without
The is a high-performance USB-C DAC (Digital-to-Analog Converter) chip favored by audiophiles for its impressive 32-bit/384kHz sampling rate and low cost . However, its compact design can lead to heat management issues, especially when paired with an external amplifier like the MAX97220 or when driving high-impedance headphones. CX31993 Core Specifications
If you search for the official "CX31993 datasheet" on the Conexant (now part of Synaptics) website, you will hit a wall. The public documentation for this chip is sparse. Most available "datasheets" are simply marketing briefs or pinout diagrams scraped from Chinese OEM forums. While it offers impressive specs like 32-bit/384kHz sampling
| Parameter | Value | Implication | |-----------|-------|--------------| | Supply Voltage (VDD) | 3.0V – 3.6V (Typ. 3.3V) | Exceeding 3.6V causes excess current draw → heat | | Core Current (Icore) | 18 mA (typical) | Baseline power ~60mW | | Headphone Amp Current (Ihp) | Up to 35 mA per channel | Total chip current can reach 88 mA | | Max Junction Temp (Tj) | 125°C | Case temp of 70°C+ indicates internal issues | | Thermal Resistance (θja) | 52 °C/W (QFN package) | Without PCB heatsinking, temp rises ~5°C per 10mW over spec |
Slide the PCB back into the aluminum housing. The thermal pad should now firmly press against the metal shell, turning the entire outer casing into a functional heatsink. The dongle shell might feel warm faster, but the internal silicon chip will stay significantly cooler, preventing thermal degradation.
Any "hot fixes" should be approached with caution and are ideally done by someone with a good understanding of electronics and the risks involved (e.g., potential for further damage).
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.