2 layers37.4 × 56.1 mm
UsbAudio
28add11/USB-charger-and-audio-PCB
A PCB with decently fast USB charging and audio playback support
40 partsMIT
2 layers60.5 × 24 mm
USB Audio Sound Card
uttkarsh-chimane/USB-Audio-Sound-CardUSB Audio Sound Card based on the PCM2706C codec, designed in KiCad.
- Size
- 60.5 × 24 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 27
- Nets
- 30
- Pads
- 93
- Tracks, vias
- 114, 17
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 30 May 2026
- Updated
- 25 Sep 2026
Overview
USB Audio Sound Card is an open-source printed circuit board by uttkarsh-chimane, from the uttkarsh-chimane/USB-Audio-Sound-Card repository on GitHub, published under the MIT licence. It is a 2-layer board of 60.5 × 24 mm with 27 parts on 30 nets, routed with 114 tracks and 17 vias.
It is built around the PCM2706CPJTR. Its parts include 12 capacitors, 11 resistors, 2 connectors, 1 IC and 1 crystal. It belongs with the audio and music boards of this library.
Main components
1README
README.md⚡ PCM2706 USB Audio Sound Card
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⚙️ What I Built
A compact USB-powered stereo audio sound card designed around the Texas Instruments PCM2706C USB Audio Codec. The device converts USB digital audio streams into analog stereo output and provides a simple plug-and-play audio interface for computers supporting the USB Audio Class standard.
🚀 Overview
This project implements a USB audio playback device using the PCM2706C USB audio codec. The design integrates USB communication, clock generation, analog audio filtering, and stereo output circuitry on a compact PCB developed in KiCad.
The board is powered directly from the USB port and outputs analog audio through a 3.5 mm audio jack.
📷 Project Gallery
🧩 3D PCB Render
🔌 PCB Layout
⚙️ Schematic
📑 Component Reference Sheet
The complete component reference sheet is available here:
The spreadsheet contains:
- Reference Designators
- Quantity
- Component Values
- Package Information
- Footprint Assignments
- Brief Component Descriptions
✨ Features
- USB Audio Class compliant architecture
- PCM2706C USB audio codec
- USB bus powered (5 V)
- Stereo analog audio output
- Integrated RC output filtering network
- 12 MHz crystal clock source
- Compact PCB footprint
- Designed using KiCad
⚒️ Hardware Architecture
USB Host
│
▼
USB Connector
│
▼
PCM2706C USB Audio Codec
│
▼
RC Output Filter
│
▼
3.5 mm Stereo Audio Jack🧠 Schematic Highlights
USB Interface
- USB D+ and D− lines routed through 22 Ω series resistors.
- Pull-up resistor used for USB device detection.
- USB bus-powered operation.
Clock Generation
- 12 MHz crystal oscillator connected to the PCM2706C.
- Load capacitors selected according to crystal requirements.
Audio Output Stage
- Analog left and right channels filtered using RC networks.
- AC coupling capacitors remove DC offset before audio output.
- Stereo output available through a 3.5 mm audio jack.
Power Integrity
- Dedicated decoupling capacitors placed near codec supply pins.
- Separate analog and digital supply filtering considerations included.
🧩 PCB Design Insights
The PCB was designed as a compact single-board implementation with:
- Short USB signal paths
- Local decoupling near the codec IC
- Crystal placement close to oscillator pins
- Dedicated analog output filtering section
- 3D mechanical verification using external component models
🧪 Applications
- USB-to-analog audio conversion
- External USB sound card prototyping
- Educational projects involving USB Audio Class devices
- Audio codec evaluation and experimentation
- Mixed-signal PCB design learning
- Embedded audio hardware development
⚠️ Limitations
This project is intended for educational and design demonstration purposes.
- No integrated headphone amplifier stage
- Design has not been physically fabricated or tested
- Intended primarily for line-level audio output
🚀 Future Improvements
- USB-C connector variant
- Headphone amplifier stage
- ESD protection circuitry
- Improved analog output filtering
- Revision B PCB optimization
🛠️ Design Software
- KiCad 10
- Custom and vendor-provided symbol libraries
- Vendor STEP/IGES mechanical models
Parts
27| Qty | Value | Footprint | References |
|---|---|---|---|
| 5 | 1µF | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | C10, C13, C14, C15, C16 |
| 4 | 3.3k | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R8, R9, R10, R11 |
| 2 | 100µF | Capacitor_THT:CP_Radial_D10.0mm_P5.00mm | C4, C5 |
| 2 | 12pF | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | C11, C12 |
| 2 | 16E | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R6, R7 |
| 2 | 22E | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R1, R2 |
| 2 | 22nF | Capacitor_SMD:C_0603_1608Metric_Pad1.08x0.95mm_HandSolder | C2, C3 |
| 1 | 1.5K | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R3 |
| 1 | 1.5k | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R4 |
| 1 | 10µF | Capacitor_THT:CP_Radial_D5.0mm_P2.00mm | C1 |
| 1 | 12MHz | Crystal:Crystal_SMD_Abracon_ABM8AIG-4Pin_3.2x2.5mm | X1 |
| 1 | 1M | Resistor_SMD:R_0603_1608Metric_Pad0.98x0.95mm_HandSolder | R5 |
| 1 | Audio Jack | STX-3000:KYCON_STX-3000 | J2 |
| 1 | PCM2706CPJTR | PJT32:PJT32 | U1 |
| 1 | USB_Type_A_Plug | 48037-1000:MOLEX_48037-1000 | J1 |
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Questions
How big is the USB Audio Sound Card PCB?
It measures 60.5 × 24 mm and has 2 copper layers, 1.6 mm thick.
What parts does the USB Audio Sound Card use?
27 parts, built around the PCM2706CPJTR. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the USB Audio Sound Card KiCad files?
From the uttkarsh-chimane/USB-Audio-Sound-Card repository on GitHub, at the commit this page was made from: the board is hardware/kiCad/project/USB Audio Sound Card.kicad_pcb and its schematic hardware/kiCad/project/USB Audio Sound Card.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the USB Audio Sound Card design in my own project?
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).