Reviewed by: Ken Appleby
A minimal working circuit includes:
Block diagram from datasheet would show:
USB PHY → USB Audio Controller → DSP (optional equalizer, bass boost) → DAC → HP Amp → 3.5mm jack.
If a visual block diagram were present in the official datasheet, it would show the following internal architecture:
The CX31993 is a highly integrated, low-power Audio Codec and Controller designed specifically for USB Type-C connectors. Unlike passive adapters that merely reroute analog signals (which require a phone with a DAC built-in), the CX31993 is an active component. It negotiates the USB-C protocol, pulls digital audio data, converts it to analog, and amplifies it. cx31993 datasheet
Since it is not public:
The CX31993 comes in a small QFN-20 or WLCSP package. Key pin groups:
Critical pins to verify:
While the official datasheet remains an exclusive document, the public performance metrics paint a clear picture. The CX31993 is a high-fidelity, low-power workhorse. It is not built for massive power (it won't drive planar magnetic headphones), but for the 99% of users with standard earbuds and IEMs, its 124dB SNR and DSD128 support offer audiophile-grade sound for less than $10 per dongle.
For engineers, the design is straightforward: a stable 24MHz clock, clean power decoupling, and careful analog ground routing are all that separates a mediocre dongle from an excellent one. For consumers, look for "CX31993" printed on the chip inside your USB-C adapter—it guarantees you are buying verified performance, not snake oil.
Disclaimer: The technical data presented here is aggregated from public test measurements (AudioScienceReview, L7Audiolab), reverse engineering efforts, and application notes. For mass production, sign an NDA with Synaptics to obtain the full, official CX31993 datasheet. A minimal working circuit includes:
The datasheet’s software section is crucial for Windows and Linux compatibility.
The CX31993 integrates three primary functional blocks:
Pinout Highlights (Typical 20-24 pin QFN package): Block diagram from datasheet would show: USB PHY