Mastering the Conexant Cx31993: Hardware Specs, Audio Quality, and Technical Fixes
Install a 5.1V TVS diode on the VBUS line right at the USB-C connector entrance to clamp voltage transients. Impedance Matching
and GND pins. Often, budget implementations skip these, causing audio-to-USB noise, or "chirping." Adding these improves the signal-to-noise ratio.
Are you designing a or modifying an existing commercial dongle ?
Snap a small ferrite core onto the USB-C cable to reduce high-frequency noise. Cx31993 Datasheet Fix
Based on verified reviews and manufacturer snippets from sites like , here’s what’s under the hood: Amplifier Class: Class G amplifier (confirmed by Framework's CEO
Before diving into hardware fixes, you must understand what the Cx31993 chip is capable of achieving under optimal conditions. Up to 32-bit / 384kHz PCM.
: Place a 1µF ceramic capacitor (X7R or X5R) in parallel with a 100nF capacitor as close as possible to the AVDDcap A cap V sub cap D cap D end-sub
Android natively downsamples audio to 48kHz via the system mixer. To bypass this and utilize the full 384kHz capability of the Cx31993, use specialized media players like UAPP (USB Audio Player Pro) , Hiby Music , or Neutron Player using Bit-Perfect mode. Are you designing a or modifying an existing
These capacitors must be placed within 1.5mm of the VREF pin, grounding directly to a solid, uninterrupted analog ground plane (AGND). This suppresses high-frequency switching noise from the internal charge pump.
The Conexant (now Synaptics) CX31993 is a highly popular, low-power USB Type-C digital-to-analog converter (DAC) chip. It powers countless budget audiophile dongles, headphones, and custom DIY audio boards. However, hardware engineers, hobbyists, and DIY enthusiasts frequently run into a major roadblock: the lack of a comprehensive, easily accessible public datasheet, combined with confusing reference designs that lead to hardware failures, poor audio quality, or recognition issues.
Windows often misidentifies the device, leading to stuttering or low-volume audio.
Solution: Enable or USB debugging in developer options. For more control, use an app like USB Audio Player Pro (UAPP) , which bypasses the Android audio system and communicates directly with the CX31993. Up to 32-bit / 384kHz PCM
Apply these hardware and schematic corrections to fix your CX31993 design. Correcting the Power Supply Circuit The analog power supply ( AVDDcap A cap V sub cap D cap D end-sub ) and digital power supply ( DVDDcap D cap V sub cap D cap D end-sub
To help me tailor any specific circuit diagrams, component choices, or troubleshooting steps for your project, please let me know:
). Connect them directly to the headphone jack through small ferrite beads (e.g., 600 ohms at 100MHz) to suppress EMI.
Ensure USB OTG (On-The-Go) is enabled in your phone's developer settings if the DAC doesn't power on immediately. Technical Reference (Hardware Specs) Conexant (CX-Pro) CX31993 USB-C Amp/DAC Review