The CX31993 is capable of an impressive >100dB SNR, but poor PCB layout destroys this performance.
A genuine CX31993 datasheet (typically a 30–50 page PDF) includes:
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If you are an electrical engineer designing a product with the CX31993, here is what you would actually use the datasheet to fix: Cx31993 Datasheet Fix
Before sending your PCB design to production, verify your implementation against this audited checklist derived from verified working implementations: Target Parameter Factory Datasheet Spec Corrected Production Spec Unspecified Ωcap omega resistors in series with HPL/HPR Microphone Bias (MIC_BIAS) Internal Pull-up Add external 2.2k Ωcap omega pull-up to AVDDcap A sub cap V cap D cap D end-sub for stability Clock Source Internal RC Oscillator External 24MHz Crystal (10ppm) for low jitter USB Resistors No external pull-downs Ωcap omega pull-downs on CC1/CC2 for Type-C detection
The chip is efficient but not a powerhouse. For high-impedance headphones (300 Ohms+), it may struggle. The "fix" here is using a dedicated external amp or choosing a different chip like the ES9281C Pro if you need more volume headroom. Conclusion
What specific are you currently seeing (e.g., device not recognized, distorted sound, noise)? The CX31993 is capable of an impressive >100dB
Isolate AVDD and DVDD using a ferrite bead. Place a 1µF ceramic capacitor close to the AVDD pin to eliminate high-frequency digital switching noise from bleeding into your audio output. Critical Firmware and Register Fixes
: This fix addresses driver conflicts, but compatibility issues can be due to the device's Android version. Some newer Android devices might not properly trigger the output for the DAC. A simple workaround is to:
If you are experiencing issues like high-frequency noise or "muddy" audio, here is how the community is addressing them: Filtering High-Frequency Noise: Some users have reported noise above If you share with third parties, their policies apply
: Using 2.2 µF on the VOUT_REF pin (pin 11). Fix : Use 1 µF ±10% X7R – larger values cause pop noise on plug-in due to slow common mode settling.
The has become a legendary chip in the budget audiophile community, powering popular USB-C DAC dongles like the Abigail and JCALLY JM6 . However, finding an official, high-quality CX31993 datasheet is notoriously difficult, as the documentation is often restricted to original equipment manufacturers (OEMs).
The pinout diagram in certain revisions of the datasheet mislabels the internal low-dropout (LDO) regulator outputs. Swapping these connections results in the digital core or the analog stage receiving unstable voltages, causing intermittent chip resets. 2. Flawed Charge Pump Capacitor Values
: Many standard music players (Spotify, Deezer, Poweramp) do not support direct audio output to a USB DAC. To fix this, you need to use a player that supports USB Exclusive Mode . Apps like Poweramp or HiBy Music allow you to enable this feature in their settings. Once enabled, these apps bypass the phone's internal audio processing and send the bit-perfect audio directly to the CX31993.
This is triggered by an incorrect descriptor value in the chip's default USB Endpoint Descriptor endpoint configuration. Flash the EEPROM to modify the bmAttributes byte from 0x01 (Asynchronous) to 0x02 (Adaptive), or use an external tool like UAC2 Control Panel to override host-side driver caching. 4. Optimized Reference Schematic Checklist