HardLabs

I2c over rj45

rmingon·i2c-over-rj45·hardware/hardware.kicad_pcb

I2c over rj45 PCB layout, top view — open source board by rmingon

About the I2c over rj45 PCB

I2c over rj45 is an open source PCB design by rmingon, published on GitHub under the CERN-OHL-S-2.0 license. It is a 2-layer board measuring 45 × 30 mm, with 9 components from 6 distinct parts.

Other key parts include the PCA9615DP. By type, the board carries 4 capacitors, 2 connectors, 2 resistors and 1 IC.

It belongs with the dev boards & breakouts designs in this gallery.

From the project

Open-source differential I²C extender: run I²C over 100 m of Cat5e using the PCA9615. KiCad sources, RJ45 wiring, and bus-recovery included.

Differential I2C extender based on the NXP PCA9615. Two identical boards, one at each end of a straight Cat5e cable, extend a local I2C bus well beyond the few tens of centimetres it normally survives.

I2C was specified for on-board communication. SDA and SCL are open-drain, pulled up by a resistor, so the rise time is set by the RC formed by that resistor and the bus capacitance — the specification caps that capacitance at 400 pF. A metre of ribbon cable already consumes most of that budget. The single-ended signals also have no noise immunity and no tolerance for ground offset between…

I2c over rj45, from the project README
From the project README

Main components on the I2c over rj45

PCA9615DP

I2c over rj45 bill of materials (BOM)

9 components, 6 distinct parts.

QtyPartRefs
1
PCA9615DP
U1
1
Conn_01x05
J1
1
8P8C_Shielded
J2
2
4.7u
C1, C4
2
100n
C2, C3
2
2.2K
R1, R2

I2c over rj45 design files

The KiCad project lives in the rmingon/i2c-over-rj45 repository on GitHub; these links point at the commit this page was built from.

I2c over rj45: common questions

How big is the I2c over rj45 PCB?

The I2c over rj45 measures 45 × 30 mm, has 2 copper layers and is 1.6 mm thick.

How many components are on the I2c over rj45?

9 components, from 6 distinct parts. The full bill of materials is listed on this page.

Where can I download the I2c over rj45 design files?

From the rmingon/i2c-over-rj45 repository on GitHub, which has the KiCad layout and the schematic; the links under Design files point to each one.

Can I use the I2c over rj45 design in my own project?

Yes, under the terms of its CERN-OHL-S-2.0 license, which rmingon chose for the repository.

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