2 layers
2 layers43.2 × 16.5 mm
Phantom
oliverpaddock/OpenMicAn open source audio interface
- Size
- 43.2 × 16.5 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 22
- Nets
- 18
- Pads
- 83
- Tracks, vias
- 75, 42
- Pours
- 1
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 8 Apr 2025
- Updated
- 25 Sep 2026
Overview
Phantom is an open-source printed circuit board by oliverpaddock, from the oliverpaddock/OpenMic repository on GitHub, published under the CERN-OHL-S-2.0 licence. It is a 2-layer board of 43.2 × 16.5 mm with 22 parts on 18 nets, routed with 75 tracks and 42 vias.
It is built around the TPS61391RTE, TPS7A4101DGN and CL21A106KAYNNNE, with the CL21A225KBQNNNE, CL21B474KBFNNNE and 0805W8F1003T5E (SMT业务专用) among its other parts. Its parts include 8 capacitors, 7 resistors, 2 ICs, 2 connectors and 1 diode.
Main components
10
TPS61391RTE
WQFN-16-EP(3x3)-40℃~+125℃@(TJ) 1 2.5V~5.5V 20V~85V 700kHz Adjustable Boost Boost Built-in No WQFN-16-EP(3x3) DC-DC Converters ROHSTexas InstrumentsDC-DC Converters
TPS7A4101DGN
MSOP-8-EP-40℃~+125℃@(Tj) 1 1.175V~48V 25uA 290mV@(20mA) 50V 50mA 65dB@(100Hz) Adjustable Over Current Protection、Thermal shutdown、Enable control、Input under-voltage protection Positive MSOP-8-EP Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSTexas InstrumentsVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
CL21A106KAYNNNE
080510uF 25V X5R ±10% 0805 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHSSamsung Electro-MechanicsMultilayer Ceramic Capacitors MLCC - SMD/SMTCL21A225KBQNNNE
08052.2uF 50V X5R ±10% 0805 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHSSamsung Electro-MechanicsMultilayer Ceramic Capacitors MLCC - SMD/SMTCL21B474KBFNNNE
0805470nF 50V X7R ±10% 0805 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHSSamsung Electro-MechanicsMultilayer Ceramic Capacitors MLCC - SMD/SMT
0805W8F1003T5E (SMT业务专用)
0805100kΩ ±1% 0805 Chip Resistor - Surface Mount ROHSUNI-ROYALChip Resistor - Surface MountCL21B103KBANNNC
080510nF 50V X7R ±10% 0805 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHSSamsung Electro-MechanicsMultilayer Ceramic Capacitors MLCC - SMD/SMTCL21A475KAQNNNE
080525V 4.7uF X5R ±10% 0805 Multilayer Ceramic Capacitors MLCC - SMD/SMT ROHSSamsung Electro-MechanicsMultilayer Ceramic Capacitors MLCC - SMD/SMT
DFE201612E-4R7M=P2
08061.2A 1.8A 252mΩ 4.7uH ±20% 0806 Power Inductors ROHSMurataPower Inductors
BAS316
SOD-3231.25V@150mA 100V 250mA 400mW 4A 4ns 500nA@80V Independent SOD-323 Switching Diodes ROHSNexperiaSwitching Diodes
README
README.mdOpenMic
OpenMic is an open-source, 2-in, 2-out, usb-c audio interface.
About
Why open source?
Open source audio/music hardware is not scarce, but general-purpose open source audio interfaces for musicians are essentially non-existent. OpenMic brings repairability, transparency, and education to an overlooked corner of music hardware.
You own your hardware. All schematics, firmware, and design files are publicly accessible so you can repair it, modify it, and understand it.
What is OpenMic?
If you aren't familiar with audio interfaces like the Focusrite Scarlett 2i2 or the Universal Audio Apollo Twin, they basically take analog audio - from a microphone, a guitar, a synth, etc. - and convert it into digital audio your computer can use in a DAW like Ableton, Logic, or Audacity. They also convert digital audio from your computer back into analog audio that you can hear through speakers or headphones. Interfaces also typically provide some sort of amplification or volume control on the inputs and outputs.
This is exactly what OpenMic does. Two inputs that can take microphone/line/instrument level signals, outputs for your speakers, and a headphone jack. Plus a few other features like phantom power that are listed in more detail in the Features section.
System block diagram
Current Status
OpenMic is currently in the prototyping stage. The circuit has been designed and simulated, and individual systems are being built and tested. View the schematics to see the current circuit design.
Progress will be posted on the OpenMic blog as prototyping continues.
Roadmap
- Initial design and component selection
- Simulation for design verification
- Subsystem prototyping
- Full board design in KiCad
- First full v1 board
- Crowd supply launch
- Production
Features
- 2 combo XLR/TRS inputs (mic/line/inst)
- Balanced TRS stereo line outputs
- TRS headphone output
- 48V phantom power
- Direct monitoring
- Up to 32-bit/96kHz
- USB-C bus powered (1.5A) with external USB-C fallback
- Drives headphones from 32Ω to 600Ω
- Fully open hardware and firmware
Getting Started
If you want to view/edit KiCAD files, make sure to add the part libraries located in /hardware/libs to your project or globally in your KiCAD instance.
Sponsors
Special Thanks
THAT Corporation
Neutrik
Parts
22| Qty | Value | Footprint | References |
|---|---|---|---|
| 4 | 200k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R2, R3, R5, R6 |
| 2 | 10k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R4, R7 |
| 2 | 10uF | Capacitor_SMD:C_1210_3225Metric_Pad1.33x2.70mm_HandSolder | C7, C8 |
| 2 | 2.2uF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C4, C5 |
| 2 | 470nF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C2, C3 |
| 1 | 100k | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R1 |
| 1 | 10nF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C6 |
| 1 | 4.7uF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C1 |
| 1 | 4.7uH | Inductor_SMD:L_Wuerth_PMCI-201610 | L1 |
| 1 | 5V | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | J1 |
| 1 | BAS316 | Diode_SMD:D_SOD-323 | D1 |
| 1 | Conn_01x03_Pin | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | J2 |
| 1 | EN | Jumper:SolderJumper-2_P1.3mm_Open_RoundedPad1.0x1.5mm | JP1 |
| 1 | TPS61391 | Package_DFN_QFN:WQFN-16-1EP_3x3mm_P0.5mm_EP1.6x1.6mm | U1 |
| 1 | TPS7A4101 | Package_SO:Texas_DGN0008B_VSSOP-8-1EP_3x3mm_P0.65mm_EP2x3mm_Mask1.88x1.98mm_ThermalVias | U2 |
Questions
How big is the Phantom PCB?
It measures 43.2 × 16.5 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Phantom use?
22 parts, built around the TPS61391RTE, TPS7A4101DGN, CL21A106KAYNNNE and CL21A225KBQNNNE. 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 Phantom KiCad files?
From the oliverpaddock/OpenMic repository on GitHub, at the commit this page was made from: the board is hardware/pcb/prototypes/power/v2-48v/phantom/phantom.kicad_pcb and its schematic hardware/pcb/main-board/codec.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Phantom design in my own project?
Its repository publishes it under the CERN-OHL-S-2.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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