skiselev/usb_audio14Compact USB Audio Adapter
Usb audio is an open-source printed circuit board by skiselev, from the skiselev/usb_audio repository on GitHub, published under the GPL-3.0 licence. It is a 2-layer board of 53.3 × 40.6 mm with 78 parts on 56 nets, routed with 698 tracks and 90 vias.
It is built around the PLR135/T8, AD8656AR and OPA2353EA, with the PCM2902CDB and REG103UA-5 among its other parts. Its parts include 32 capacitors, 27 resistors, 6 ICs, 4 connectors and 3 switches. It belongs with the audio and music boards of this library.
I was looking for a USB audio adapter for my Intel Galileo projects, and surprisingly I was not able to find a compact USB audio adapter which will offer line input or digital (optical) input and output. Most USB audio dongles available on the market are intended to be used with a headset and only offer monophonic microphone input. One exception was Behringer UCA202 which is bulky for my projects. And so I've designed this adapter.
This USB Audio adapter can be used with small SBCs like Intel Galileo, Raspberry Pi, or BeagleBone Black to provide high quality audio input and output. Its size is only 2.1 x 1.6 inches (53.44 x 40.74 mm). This USB Audio adapter will also work with regular PCs, Android based smartphones and tablets, or almost everything else that supports USB audio. It is based on popular Texas Instruments (was Burr Brown) PCM2902C, and schematic mostly follows Texas Instrument's reference design.
As mentioned above the main component is Texas Instruments PCM2902 USB audio codec IC (U1). Additionally the circuit uses Texas Instruments REG103UA LDO IC for conditioning power for the analog circuitry (U2) and a pair of dual channel operational amplifier ICs that work as low pass filters for input and output (U5 and U6).
There is a lot of flexibility in the design:
Due to project's size and component availability the project mostly uses SMT components. I used through hole components for components that are subject to physical stress (connectors and buttons). It it is not too difficult to solder SMT components it with some practice. Here are some tips:
USB Audio project on Mouser.com - View and order all components except of the PCB, screws and nuts.
USB Audio project on OSH Park - View and order PCB.
| Component type | Reference | Description | Quantity | Possible sources and notes |
|---|---|---|---|---|
| PCB | USB Audio PCB - V2 | 1 | Order at OSH Park or from any other PCB manufacturer using Gerber files from gerber folder. | |
| Capacitor | C1 - C3 | 22pF C0G SMT 0603 capacitor | 3 | Mouser 77-VJ0603A220JXACBC. Note: C3 is not needed if not implementing optical S/PDIF input. |
| Capacitor | C4 - C7 | 330pF C0G SMT 0805 capacitor | 4 | Mouser 77-VJ0805A331KXACBC |
| Capacitor | C8 - C11 | 1.8nF C0G SMT 0805 capacitor | 4 | Mouser 81-GRM215C1H182JA01D |
| Capacitor | C12, C13 | 100nF X7R SMT 0805 capacitor | 2 | Mouser [80-C0805C104K3R7210](https://www.mouser.com/ProductDetail/80-C0805C104K3R7210]. Note: These capacitor are not needed if not implementing optical S/PDIF input and output. |
| Capacitor | C14 - C20 | 1uF X7R SMT 0805 capacitor | 7 | Mouser [80-C0805C105K4R](https://www.mouser.com/ProductDetail/80-C0805C105K4R] |
| Capacitor | C21 - C30 | 10uF tantalum SMT capacitor | 10 | Mouser 74-593D106X9016A2TE3 |
| Capacitor | C31, C32 | 220uF tantalum SMT capacitor | 2 | Mouser 581-TLNT227M010R1300. Note: Use the recommended value if driving low impedance loads (for example headphones). For high impedance loads (e.g. line output connected to an amplifier) cheaper 10uF capacitors can be used. See previous line for part number. |
| Schottky Diode | D1 | Schottky diode with low voltage drop (350mV) | 1 | Mouser 771-PMEG2010ER115 |
| LED | D2 | 0603 LED | 1 | Mouser 78-VLMTG1300-GS08. Any color can be used :-) The suggested part is "pure" green. It is too bright to my taste, so if using it consider increasing value of R8. Or use "conventional" green and save a few cents. |
| Inductor | L1 | 47uH SMT 0805 inductor | 1 | Mouser 963-LBR2012T470K. Note: This inductor is not needed if not implementing optical S/PDIF input. |
| Connector | P1 | Micro USB receptacle with through hole pegs | 1 | Mouser 649-10118194-0001LF. Note: Use either P1 or P2 |
| Connector | P2 | Pin Header 5x1, 2.54 mm lead spacing | 1 | Mouser 649-68000-105HLF. Note: Use either P1 or P2 |
| Connector | P3 | 3.5 mm stereo audio jack, blue | 1 | Mouser 806-STX-31203B284C |
| Connector | P4 | 3.5 mm stereo audio jack, green | 1 | Mouser 806-STX-31203B577C |
| Resistor | R1 - R3 | 2.2 ohm 1% SMT 0603 resistor | 3 | Mouser 71-CRCW0603-2.2-E3. Note: For R2 and R3 use the recommended value if driving low impedance loads. For high impedance load resistance can be increased to 100 ohm. See R6, R7 line for part number. |
| Resistor | R4, R5 | 22 ohm 1% SMT 0603 resistor | 2 | Mouser 71-CRCW0603-22-E3 |
| Resistor | R6, R7 | 100 ohm 1% SMT 0603 resistor | 2 | Mouser 71-CRCW0603100RFKEB |
| Resistor | R8 | 470 ohm 1% SMT 0603 resistor | 1 | Mouser 71-CRCW0603470RFKEB |
| Resistor | R9 - R12 | 1.5 Kohm 1% SMT 0603 resistor | 4 | Mouser 71-CRCW0603-1.5K-E3 |
| Resistor | R13 - R16 | 3.9 Kohm 1% SMT 0603 resistor | 4 | Mouser 71-CRCW0603-3.9K-E3 |
| Resistor | R17 - R24 | 12 Kohm 1% SMT 0603 resistor | 8 | Mouser 71-CRCW0603-12K-E3 |
| Resistor | R25 | 13 Kohm 1% SMT 0603 resistor | 1 | Mouser 71-CRCW0603-13K-E3 |
| Resistor | R26 | 27 Kohm 1% SMT 0603 resistor | 1 | Mouser 71-CRCW0603-27K-E3 |
| Resistor | R27 | 1 Mohm 1% SMT 0603 resistor | 1 | Mouser 71-CRCW06031M00FKEB |
| Switch | SW1 - SW3 | 6 mm x 6 mm tactile switch | 3 | Mouser 653-B3F-1050 |
| Switch Key Top | SW1 | 4 mm x 6 mm tactile switch key top, red | 1 | Mouser 653-B32-1080 |
| Switch Key Top | SW2 | 4 mm x 6 mm tactile switch key top, green | 1 | Mouser 653-B32-1050 |
| Switch Key Top | SW3 | 4 mm x 6 mm tactile switch key top, blue | 1 | Mouser 653-B32-1040 |
| Integrated Circuit | U1 | Texas Instruments PCM2902C | 1 | Mouser 595-PCM2902CDB |
| Integrated Circuit | U2 | Texas Instruments REG103UA-A | 1 | Mouser 595-REG103UA-A |
| Optical Receiver Module | U3 | Everlight PLR135/T8 | 1 | Mouser 638-PLR135T8. Note: This module is not needed if not implementing optical S/PDIF input. |
| Optical Transmitter Module | U4 | Everlight PLT133/T8 | 1 | Mouser 638-PLT133T8. Note: This module is not needed if not implementing optical S/PDIF output. |
| Integrated Circuit | U5 | Texas Instruments OPA2353 | 1 | Mouser 595-OPA2353UA |
| Integrated Circuit | U6 | Analog Devices AD8656 | 1 | Mouser 584-AD8656ARZ |
| Crystal Resonator | X1 | 12 MHz | 1 | Mouser 774-445C25D12M00000 |
| Component type | Description | Quantity | Possible sources and notes |
|---|---|---|---|
| 3D Printed Part | USB Audio Case Top | 1 | 3D Print USB Audio Case Top |
| 3D Printed Part | USB Audio Case Bottom | 1 | 3D Print USB Audio Case Bottom |
| Screw | M3 x 10mm socket cap screw | 2 | Fastenal MS2510010A20000 |
| Nut | M3 square nut | 2 | Fastenal 0161907 |
| Qty | Value | Footprint | References |
|---|---|---|---|
| 10 | 10uF | SM1206POL | C21, C22, C23, C24, C25, C26, C27, C28, C29, C30 |
| 8 | 12k | SM0603_Resistor | R17, R18, R19, R20, R21, R22, R23, R24 |
| 7 | 1uF | SM0805 | C14, C15, C16, C17, C18, C19, C20 |
| 4 | 1.5k | SM0603_Resistor | R9, R10, R11, R12 |
| 4 | 1.8nF | SM0805 | C8, C9, C10, C11 |
| 4 | 3.9k | SM0603_Resistor | R13, R14, R15, R16 |
| 4 | 330pF | SM0805 | C4, C5, C6, C7 |
| 3 | 2.2 | SM0603_Resistor | R1, R2, R3 |
| 3 | 22pF | SM0603_Capa | C1, C2, C3 |
| 2 | 100 | SM0603_Resistor | R6, R7 |
| 2 | 100nF | SM0805 | C12, C13 |
| 2 | 22 | SM0603_Resistor | R4, R5 |
| 2 | 220uF | SM1210L | C31, C32 |
| 2 | CONN_1 | Hole_3mm | HOLE1, HOLE2 |
| 1 | 12MHz | Crystal_5.0x3.2mm | X1 |
| 1 | 13k | SM0603_Resistor | R25 |
| 1 | 1M | SM0603_Resistor | R27 |
| 1 | 27k | SM0603_Resistor | R26 |
| 1 | 470 | SM0603_Resistor | R8 |
| 1 | 47uH | SM0805 | L1 |
| 1 | AD8656 | SOIC-8N | U6 |
| 1 | LINE_IN | Conn_Audio_3.5mm_Stereo | P3 |
| 1 | LINE_OUT | Conn_Audio_3.5mm_Stereo | P4 |
| 1 | MUTE | SW_Tact_6mm | SW1 |
| 1 | OPA2353 | SOIC-8N | U5 |
| 1 | PCM2902C | SSOP-28 | U1 |
| 1 | PLR135/T8 | Everlight-T8 | U3 |
| 1 | PLT133/T6A | Everlight-T8 | U4 |
| 1 | POWER | LED-0603 | D2 |
| 1 | REG103UA | SOIC-8N | U2 |
| 1 | USB | Conn_Micro_USB_B | P1 |
| 1 | USB_HEADER | PIN_ARRAY_5x1 | P2 |
| 1 | VF350mV | SOD103W | D1 |
| 1 | VOL_DOWN | SW_Tact_6mm | SW3 |
| 1 | VOL_UP | SW_Tact_6mm | SW2 |
Geophysical-Instrumentation-Group-UL/Geophysical-Open-Seismic-Hardware
Hardware and firmware of the Geophysical Open Seismic Hardware project. The goal is to stimulate open development in geophysical instrumentation
gitter-badger/wiggleport
Modular I/O for multi-channel sound, light, and motion
PCBench/PCBench
resolution = [0.5, 0.5] pcbfolder = '../PCBs/' pcbnames = ["1Bitsy1bitsy"] iters = 30 env = PCBRoutingEnv(resolution=resolution, pcbfolder=pcbfolder, pcbnames=pcbnames) obs, info = env.reset() for in range(iters): act =…
It measures 53.3 × 40.6 mm and has 2 copper layers, 1.6 mm thick.
78 parts, built around the PLR135/T8, AD8656AR, OPA2353EA and PCM2902CDB. 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.
From the skiselev/usb_audio repository on GitHub, at the commit this page was made from: the board is KiCad/usb_audio.kicad_pcb. PCBKit opens the board in the browser, with nothing to install.
Its repository publishes it under the GPL-3.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).