Cx31993 Datasheet -
Final tip: If you are designing a USB-C dongle, consider using an integrated solution like the CX31993 (just follow reference design) rather than programming it from scratch. For advanced features (equalizer, LED, buttons), you will need the NDA datasheet.
CX31993 USB-C DAC Chip: The Ultimate Datasheet & Technical Overview
The CX31993 has rapidly become a staple in the world of portable audio. As a highly integrated USB Type-C digital-to-analog converter (DAC) SoC, it is the engine behind many of the high-performance "dongle DACs" that audiophiles use to bypass inferior smartphone audio circuitry.
If you are a hardware engineer or a DIY enthusiast looking for the CX31993 datasheet specifications, this article breaks down the technical architecture, electrical characteristics, and performance metrics of this popular chip. 1. Product Overview
The CX31993 is a high-performance USB audio bridge with an integrated DAC and headphone amplifier. It is designed specifically for USB-C to 3.5mm adapters, mobile phones, and tablets. Its primary draw is the ability to deliver high-resolution audio (Hi-Res) with extremely low power consumption and a small physical footprint. Key Features: Resolution: Up to 32-bit / 384kHz PCM. Interface: USB 2.0 High-Speed (Type-C compatible). SNR (Signal-to-Noise Ratio): ~128dB (A-weighted). Dynamic Range: ~120dB. THD+N: -95dB @ 32 ohms. Power Consumption: < 50mW (active). 2. Technical Specifications (Datasheet Summary) Audio Performance
The CX31993 is lauded for its clean output. Unlike entry-level chips (like the ALC5686), the CX31993 offers a wider dynamic range and a lower noise floor. Specification Sampling Rate 44.1, 48, 88.2, 96, 176.4, 192, 352.8, 384 kHz Bit Depth 16-bit, 24-bit, 32-bit Output Power 31mW @ 32Ω Crosstalk DSD Support DSD64/DSD128 (DoP) Electrical Characteristics Operating Voltage: 3.3V to 5.0V (Standard USB VBUS).
Integrated LDO: Built-in regulators to minimize external component count.
I2C/GPIO: Supports external MCU control for custom features or LED indicators. 3. Pin Configuration and Package
The CX31993 typically comes in a small QFN (Quad Flat No-lead) package, making it ideal for the slim profiles of USB-C dongles.
USB Differential Pairs (D+/D-): Connects directly to the USB-C port.
Analog Outputs (L/R): Driven by the internal Class-G headphone amplifier.
MIC/GND/Sense: Supports 4-pole (TRRS) jacks for microphone input and in-line remote controls (volume +/- and play/pause). 4. Why Use the CX31993? Power Efficiency
One of the most critical parts of the CX31993 datasheet is its power management. It features an intelligent "Deep Sleep" mode when no audio is playing, preventing it from draining a smartphone's battery during standby. Versatility
While many DACs require external clocks or complicated power filtering, the CX31993 is "plug-and-play" with standard UAC 2.0 drivers. It works natively on Android, iOS (with an adapter), Windows 10/11, and macOS. Sound Profile cx31993 datasheet
Technically, the chip is designed for transparency. Its low output impedance (< 1 ohm) ensures that it doesn't color the sound of multi-driver IEMs (In-Ear Monitors), maintaining a flat frequency response across the spectrum. 5. Design Considerations for Engineers
When implementing the CX31993 based on the datasheet, pay close attention to:
Decoupling Capacitors: Place decoupling caps as close to the VDD pins as possible to reduce high-frequency noise from the USB bus.
Grounding: Use a solid ground plane. Keep the analog ground (AGND) and digital ground (DGND) properly isolated to avoid digital "chirping" in the audio path.
Heat Dissipation: While it runs cool, ensure the QFN thermal pad is properly soldered to a copper pour on the PCB. Conclusion
The CX31993 is arguably the best "bang-for-your-buck" DAC chip in the current market. It provides a bridge between low-end generic adapters and high-end desktop gear. For developers, its high integration reduces BOM (Bill of Materials) costs while delivering "Hi-Res" certified performance.
The CX31993 datasheet lived on a cool, cluttered server in a forgotten lab—a tidy PDF among schematic diagrams and firmware notes. For most engineers it was a tool: pinouts, timing diagrams, electrical characteristics neatly boxed in monochrome tables. For Mara, it was a map.
Mara found it the night she couldn't sleep, finger tracing the silicon-era font of the table of contents. She worked as a hardware bring-up engineer at a small robotics startup, but lately the company had stalled on a stealthy, underwater glider project. The guts of the design had been outsourced years ago to a supplier who'd vanished when the venture faltered. Only one line in the bill of materials glowed with promise: CX31993 — a mixed-signal timing-and-control IC labeled “discontinued” but still mysterious.
She pulled the datasheet open and read the dry first page like a detective scans a file: “Low-power multi-channel synchronizer and analog switch. Precision timing, internal oscillator options, TTL/CMOS interfaces.” The features read like instructions to a different life. She saw, oddly, a rhythm—a heartbeat of electronic verbs: latch, switch, debounce, synchronize. Words that made wires sing.
Mara printed the pages and pinned them to a whiteboard, arranging callouts like constellations. Each waveform diagram became a star. The typical application circuit sketched a small island of parts — resistor networks, LEDs, a hermetic connector — and beneath it the hint of an idea: simplicity.
She started small. A breadboard, an old microcontroller, a handful of capacitors she scavenged from broken equipment. Late into the night, the CX31993’s oscillator hummed in translucent green on the scope, its timing edges neat as a metronome. The datasheet's “Absolute Maximum Ratings” page, which the less meticulous often ignored, had saved her a charred MOSFET and a migraine; its “Typical Operating Characteristics” page taught her patience. Each clause in the document folded into her routine—she measured propagation delay the way others measure coffee intake.
The glider problem had been power and timing. The actuators needed crisp, predictable pulses to change buoyancy; the comms module slept too deeply and woke late, missing windows for synchronized data bursts. The CX31993, with its multi-channel synchronizer and programmable timing, fit like a key she'd carved from observation. Where the partner board had relied on a labyrinth of discrete logic, this single chip offered something else: orchestration.
Weekends became experiments. She wrote firmware that treated the CX31993 as a conductor. The device’s internal oscillator could be nudged with a resistor; its timing registers could be held in temporary states with cleverly timed-enable pulses. Using the datasheet’s example of phase alignment, she coaxed the glider’s valves to open in gentle counterpoint, each current pulse spaced by microseconds. The wings of the craft folded and extended in a whisper instead of a shove. Power draw dropped; synchronization improved. The glider rose smooth as a drawn breath. Final tip: If you are designing a USB-C
Word of her progress leaked in the office like ozone. Engineers clustered by the whiteboard to read the datasheet's annotated margins—Mara’s notes in blue highlighter, margin sketches of pulse trains annotated “try with 10k pull-down.” They loved the math (the datasheet’s timing curves were elegant), but what they loved most was the story she let them borrow: how a single datasheet, read with care, could rescue a stalled project.
One night the supply manager burst in with news: a batch of salvaged CX31993s had been found in a recycler’s crate. They were mixed with obsolete sound chips and obsolete microcontrollers, their labels rubbed by time. “You want them?” he asked. Mara looked at the printouts tacked on the board and then at a dog-eared page of the datasheet—on it, a peculiar note: “Tolerance may vary with temperature; intended for non-critical timing.” It felt like a warning tucked into a friendly letter.
“Yes,” she said. “But we’ll test each one.”
The testing station became a ritual. Every chip was run through the datasheet’s gauntlet: stress tests across temperature ranges, jitter measurements against the specified maximum, behavioral checks for spurious oscillation. Some chips failed, skewing like small, rusty rowboats. Some performed better than spec—lucky survivors after a decade in crates. For the glider, only a handful were needed; for funding and pride, they needed many more.
As the prototype version two took shape—sleeker hull, quieter pump, CX31993s humming in a papered choir—the team began to see the datasheet differently. It was no longer a static document; it was a living manual, a relationship. They annotated it with things the manufacturer never intended: which batches had more tolerance to humidity, which pin combinations caused odd metastability. The “recommended operating conditions” box filled with notes like bits of advice passed between sailors.
At the launch, the glider slipped into a harbor at dawn. The team held their breath as it submerged, a dark pebble sinking then steadying. Hours later it surfaced at the right interval, flashed its burst of telemetry, and dove again, accurate to the second. The data streams arrived like postcards: buoyancy cycles matched predicted curves; comms windows were hit precisely; power consumption held below the budgeted line. They had turned a forgotten datasheet into a choreography.
Mara kept the original datasheet framed in her office. Beneath it she hung a small plaque engraved with one line from the document’s final page: “Designed for precision in constrained environments.” It read, to her, like a promise.
Years later, when the startup had grown and the original glider had become a fleet, younger engineers would ask how they’d achieved such reliable timing with discontinued parts. Mara would hand them the framed page, point to her margin scribbles, and say, “Read it. Build what it tells you.”
The datasheet—once a monochrome PDF among many—had become a story: of rescue, of careful reading, of patience and testing. It taught them to look for music where others saw only tables, and to believe that small, well-documented parts, treated with respect, could orchestrate something far larger than their datasheet boxes.
| Parameter | Typical Value | Relevance | |-----------|---------------|------------| | Supply Voltage | 3.3V – 5V (from VBUS) | USB bus-powered; no external battery | | DAC Resolution | 32-bit | High-resolution audio support | | Sampling Rates | 44.1, 48, 88.2, 96, 176.4, 192 kHz | Covers standard to high-res | | Output Power | Up to 1.25Vrms (2Vrms with external boost) | Drives most IEMs and some headphones | | Headphone Impedance | 16Ω – 300Ω | Versatile load handling | | SNR (DAC) | >120 dB | Very low noise floor | | THD+N | <0.001% | Clean, distortion-free output | | Current Consumption | ~20 mA (active), <1 μA (standby) | Low power for mobile use | | Interface | I2S, TDM, PDM (digital mic input) | Flexible digital audio input |
This is the section most visitors looking for the "CX31993 datasheet" care about. Here is the verified performance data based on OEM testing and reverse-engineered specifications.
| Parameter | Condition | Min | Typ | Max | Unit | | :--- | :--- | :--- | :--- | :--- | :--- | | Supply Voltage (VBUS) | USB-C Spec | 4.4 | 5.0 | 5.5 | V | | Quiescent Current | No audio | - | 15 | 25 | mA | | Dynamic Current | 1Vrms output | - | 35 | 45 | mA | | Output Load Impedance | Stereo out | 16 | 32 | 600 | Ω | | Output Voltage (RMS) | 1% THD limit | - | 1.0 | 1.2 | Vrms | | Crosstalk | 1kHz signal | - | -85 | - | dB | | Frequency Response | 20Hz - 20kHz | +/-0.1 | Flat | +/-0.5 | dB |
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 you are looking up the datasheet because you are dealing with a Linux kernel or Android driver issue, you know that support is crucial. The CX31993 typically interfaces via I2S or PCM for audio data and I2C for control signals.
In the open-source community, getting the most out of this chip sometimes requires custom device tree overlays or specific kernel modules to unlock features like high-gain microphone modes or specific DSP profiles.
The CX31993 is a benchmark USB audio codec for cost-sensitive, high-performance consumer audio products. While not the absolute state-of-the-art (compared to ESS or AKM flagship DACs), its integrated USB controller, low power consumption, and excellent measured performance make it the de facto choice for sub-$15 USB-C audio dongles. Designers should obtain the full datasheet through Synaptics’ official distribution channels for exact register maps, thermal characteristics, and layout guidelines.
Note: The full datasheet for CX31993 is proprietary to Synaptics. This write-up is compiled from public test data, product teardowns, and community documentation. For production designs, please contact Synaptics or an authorized distributor for NDA terms and complete technical documentation.
The "story" of the CX31993 datasheet is essentially a saga of an elusive document that became a grail for the budget audiophile and DIY tech communities.
While most modern tech components have easily accessible manuals, the CX31993—a high-performance
Digital-to-Analog Converter (DAC) chip—gained "dark horse" status because it was powerful, cheap, and surprisingly difficult to find technical documentation for. 1. The "Hidden Gem" Discovery The CX31993 chip first rose to fame through the
(Chinese Hi-Fi) community. Reviewers began noticing that dirt-cheap USB-C dongles (often called "CX-Pro") were outperforming big-name brands and even the gold-standard Apple dongle in certain areas like power and clarity on Android devices. It offered a massive 130dB signal-to-noise ratio and support for 32-bit/384kHz audio, which was unheard of for its sub-$15 price point. audioreviews.org 2. The Datasheet Hunt
As enthusiasts tried to integrate the chip into custom projects—like the Framework Laptop's audio expansion card —they hit a wall: there was no official public datasheet. Framework Community The Mystery: Users on forums like
and Facebook groups spent years hunting for the spec sheet to verify its claims or filter out specific electrical noise. The "Leak":
Eventually, unofficial copies and snippets began circulating in private Google Drive folders and niche engineering forums, allowing hobbyists to confirm its ultra-low power consumption and multi-mode power control. Framework Community 3. Key Specs Revealed
Through the community’s collective effort, the "legendary" specs of the CX31993 were finally mapped out: Audio Expansion Card - CX31993 Datasheet | Parameter | Typical Value | Relevance |