4 layers68 × 34 mm
PicoChainReference
jasonalexander-ja/PicoChain
Power and I2C daisy chained over ethernet patch cables.
22 parts1MIT
4 layers68 × 50 mm
PicoChainZero
jasonalexander-ja/PicoChain1Power and I2C daisy chained over ethernet patch cables.
- Size
- 68 × 50 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 41
- Nets
- 77
- Pads
- 227
- Tracks, vias
- 321, 46
- Pours
- 4
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 12 Aug 2024
- Updated
- 11 Aug 2025
Overview
PicoChainZero is an open-source printed circuit board by jasonalexander-ja, from the jasonalexander-ja/PicoChain repository on GitHub, published under the MIT licence. It is a 4-layer board of 68 × 50 mm with 41 parts on 77 nets, routed with 321 tracks and 46 vias.
It is built around the SIP32419EVB, FT232RL and SRV05, with the LM78M05CH, PCA9615DP and RJ45 among its other parts. Its parts include 12 capacitors, 11 resistors, 8 connectors, 7 ICs and 2 fuses. It belongs with the interfaces and adapters boards of this library.
Main components
6SIP32419EVB
-ModulesVishay Intertechnology
FT232RL
SSOP-28-208mil-40℃~+85℃ 3.3V~5.25V、4V~5.25V USB 2.0 USB to UART SSOP-28-208mil USB Converters ROHSFTDIUSB Converters
SRV05
SOT-23-6-40℃~+85℃ 0.6pF 100nA 13V、19V 5V 6A@8/20us 8.5V 84W@8/20us ESD Four channels IEC 61000-4-2、IEC 61000-4-5 Unidirectional SOT-23-6 ESD and Surge Protection (TVS/ESD) ROHSTWGMCESD And Surge Protection (TVS/ESD)LM78M05CH
TO-3-40℃~+125℃ 1 35V 3mA 40uV 500mA 5V 78dB@(120Hz) Fixed Over Current Protection、Over Temperature Protection Positive TO-3 Voltage Regulators - Linear, Low Drop Out (LDO) Regulators ROHSTexas InstrumentsVoltage Regulators - Linear, Low Drop Out (LDO) Regulators
PCA9615DP
TSSOP-10_3.0x3.0x0.5PTSSOP-10(3x3x0.5) New Arrivals ROHSNXP SemiconductorsUncategorised
RJ45
TH-12PTH-12P SMT ROHSJLCPCB AssemblyUncategorised
README
README.mdPicoChain
Pico(Daisy)Chain is a simple standard for creating daisy chains of connected devices, allowing I2C and power to be easily distributed out using ethernet patch cables.
This is a repository containing documentation and reference hardware + software implementations.
All hardware reference implementations are in KiCAD 8+ format with the PCB layout and Gerbers.
Contents:
- PicoChainReference; A generic reference design breaking out the power and I2C to pin headers, this can be easily adapted to what ever purpose is desired.
- PicoChainZero; A reference design using the Raspberry Pi Zero as a I2C controller, breaks out the Pi Zero's serial to a USB-C connector.
- PicoChainTerminator; A reference design for a termination endpoint device, one of these needs to be present at the start and end of a chain.
Design Overview
PicoChain uses differential I2C, 12 + 24 volts, all sent down a single RJ45 & twisted pair allowing communication and power for microcontrollers + motors to be supplied using commonly available ethernet patch cables.
Generation of the differential I2C is handled by the NXP PCA9615 meaning that when SCL and SCA is hooked up to this chip, all the same I2C libraries and implementation automatically work with no further modifications.
The 12 + 24 volts is supplied with the assumption that this will be regulated into the relevant required voltages by the connected devices, the reference implementations regulates a 5V for the microcontroller and a 5V for servo and similar small motors off of the 12V line, and a 12V line is regulated off of the 24V line intended for high power motors.
Each PicoChain device has 2 RJ45 connectors to send and receive power and data, they don't have a particular direction are all the reference designs have the RJ45s passively connected, tapping off of power and I2C as needed, however, all PicoChain chains need terminators at either end.
Generally, this is designed for running sequences across some connected devices, with the idea that only 1 large load (I.E. a motor) will be running at a time, reducing the current load going through the patch cables and chained devices.
Pinout
| RJ45 Pin | Function |
|---|---|
| 1 | GND |
| 2 | +24V |
| 3 | DSDAM |
| 4 | DSCLM |
| 5 | DSCLP |
| 6 | DSDAP |
| 7 | GND |
| 8 | +12V |
Pins 3-6 (inclusive) are generated by the PCA9615 and are connected directly to ICs on each device.
Parts
41| Qty | Value | Footprint | References |
|---|---|---|---|
| 5 | 10uF | Capacitor_SMD:C_0805_2012Metric | C5, C6, C10, C12, C13 |
| 4 | 100K | Resistor_SMD:R_0805_2012Metric | R6, R7, R10, R11 |
| 3 | 470K | Resistor_SMD:R_0805_2012Metric | R3, R4, R9 |
| 2 | 10uF | Capacitor_Tantalum_SMD:CP_EIA-3216-18_Kemet-A | C4, C8 |
| 2 | 2K | Resistor_SMD:R_0805_2012Metric | R5, R8 |
| 2 | 330nF | Capacitor_Tantalum_SMD:CP_EIA-3216-18_Kemet-A | C1, C2 |
| 2 | 47nF | Capacitor_SMD:C_0805_2012Metric | C7, C11 |
| 2 | 5.1K | Resistor_SMD:R_0805_2012Metric | R1, R2 |
| 2 | Conn_01x02_Pin | Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical | J7, J8 |
| 2 | Fuse | Fuse:Fuse_0805_2012Metric | F3, F4 |
| 2 | RJ45 | Connector_RJ:RJ45_Amphenol_54602-x08_Horizontal | J1, J2 |
| 2 | SRV05 | Package_TO_SOT_SMD:SOT-23-6 | U3, U5 |
| 2 | SiP32419 | Package_DFN_QFN:DFN-10-1EP_3x3mm_P0.5mm_EP1.65x2.38mm | U6, U8 |
| 1 | +12V In | TerminalBlock_Phoenix:TerminalBlock_Phoenix_MKDS-1,5-2-5.08_1x02_P5.08mm_Horizontal | J5 |
| 1 | +24V In | TerminalBlock_Phoenix:TerminalBlock_Phoenix_MKDS-1,5-2-5.08_1x02_P5.08mm_Horizontal | J6 |
| 1 | 1nF | Capacitor_SMD:C_1206_3216Metric | C3 |
| 1 | D_Schottky | Diode_SMD:D_SMA | D1 |
| 1 | FT232RL | Package_SO:SSOP-28_5.3x10.2mm_P0.65mm | U2 |
| 1 | LM78M05 | Package_TO_SOT_SMD:TO-252-2 | U1 |
| 1 | PCA9615DP | Package_SO:TSSOP-10_3x3mm_P0.5mm | U4 |
| 1 | Raspberry Pi | Connector_PinHeader_2.54mm:PinHeader_2x20_P2.54mm_Vertical | J3 |
| 1 | USB_C_Receptacle_USB2.0_14P | Connector_USB:USB_C_Receptacle_GCT_USB4085 | J4 |
More from jasonalexander-ja/PicoChain
2- 4 layers17 × 32 mm
PicoChainTerminator
jasonalexander-ja/PicoChain
Power and I2C daisy chained over ethernet patch cables.
10 parts1MIT
Similar boards
- 2 layers100 × 50 mm
Dew Controller
kuellenberg/Dew-Controller
Dew heater controller for telescope dew heater straps
92 parts2 - 2 layers65 × 56 mm
- 2 layers
- 2 layers44.5 × 25.4 mm
SparkFun QwiicBus Endpoint
kornpow/sparkfun-kicad
Converting SparkFun OSH Eagle resources to KiCAD
76 parts - 4 layers100 × 100 mm
MOBO V2
robotique-udes/Exo_Electric
This repo contains all the information about the PCB and electrical schematics of Biogenius.
82 parts1GPL-2.0 - 2 layers31.1 × 73 mm
Testing board
RomLab/pcb-system-for-underfloor-heating-v2.0
PCB for underfloor heating system
53 parts1 - 4 layers126.2 × 94 mm
- 2 layers93 × 173 mm
Batch 1
CDFER/Business-Cards
Showcasing a collection of functional PCB business cards, each demonstrating a unique embedded electronics project.
479 parts9
Questions
How big is the PicoChainZero PCB?
It measures 68 × 50 mm and has 4 copper layers, 1.6 mm thick.
What parts does the PicoChainZero use?
41 parts, built around the SIP32419EVB, FT232RL, SRV05 and LM78M05CH. 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 PicoChainZero KiCad files?
From the jasonalexander-ja/PicoChain repository on GitHub, at the commit this page was made from: the board is PicoChainZero/PicoChainZero.kicad_pcb and its schematic PicoChainReference/PicoChainReference.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the PicoChainZero 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).