The CX31993 is a USB Audio Class 2.0 device. Sometimes Windows erroneously assigns a Class 1.0 driver.
If you’ve landed on this page searching for a you are likely one of two types of people: an audio hardware engineer trying to understand the pinout of the Conexant CX31993 chip, or—more commonly—a frustrated user whose USB-C dongle DAC (Digital-to-Analog Converter) isn’t working properly.
The internal amplifier of the CX31993 is sometimes pre-configured to output max gain, boosting the inherent noise floor of highly sensitive multi-driver IEMs.
The CX31993 features an impedance-sensing auto-gain mechanism that can limit power output for low-impedance headphones. To "fix" this and unlock full power, connect a high-impedance adapter or leave the 3.5mm plug empty when first plugging the USB-C end into your device, then plug in your headphones. Cx31993 Datasheet Fix
For optimal performance on Android and Windows, use applications that support bit-perfect exclusive hardware access (like USB Audio Player Pro or Foobar2000 with WASAPI/ASIO drivers) to bypass internal OS mixers that compress the dynamic range of the CX31993.
When implementing this chip, three primary symptoms indicate a configuration error:
This pin is highly sensitive to EMI. Standard datasheets suggest a 1µF capacitor, but resolving low-frequency hum requires upgrading this to a 4.7µF low-ESR tantalum capacitor tied tightly to analog ground. The CX31993 is a USB Audio Class 2
If your paper focuses on addressing common issues with this chip, consider these documented observations:
If Windows shows an "Unrecognized Device" error, try using a different USB-C to USB-A adapter if connecting to a PC; many bundled adapters have high failure rates.
The CX31993’s native driver (Microsoft’s inbox driver) has poor low-latency performance; ASIO4ALL acts as a buffer manager. The internal amplifier of the CX31993 is sometimes
Early datasheet revisions transpose the labels for the differential audio outputs and microphone inputs.
Lowers DC resistance to maximize power delivery to headphones X7R or X5R dielectric materials only
