Soldered RJ45 MagJack breakout

The RJ45 MagJack Breakout puts an Ethernet socket on a small board, with every pin on one 2.54 mm header. MagJack means the isolation transformers (the magnetics every Ethernet port needs) sit inside the socket, so your Ethernet chip's transmit and receive pins connect straight to the header.

The socket is the HanRun HR913550A for 10/100 Mbit Ethernet. It has a green and a yellow LED, and both legs of each LED are on the header, so you choose which chip signal lights them.

The header carries TD+, TD-, RD+ and RD-, the transmit and receive centre taps, chassis ground, the four LED pins and the shield. Solder it to the bottom and the board goes into a breadboard. Two 3.2 mm holes let you screw it down.

Note:

• The LEDs have no resistors on the board. Add one in series with each LED.
• P4 and P5 are the centre taps, the middle points of the transformer windings. Connect them the way your Ethernet chip's datasheet shows.
• Connect CHS GND (P8) and SH to the ground of your circuit.
• The header pins come unsoldered.

• Connector: HanRun HR913550A, RJ45 with integrated magnetics, shielded
• Ethernet: 10/100Base-T
• Isolation: 2250 V DC
• LEDs: green and yellow, no resistors fitted
• Pins: P1 TD+, P2 TD-, P3 RD+, P4 TX centre tap, P5 RX centre tap, P6 RD-, P7 NC, P8 chassis GND, G+, G-, Y+, Y-, SH
• Header: 13-pin, 2.54 mm pitch, unsoldered
• Dimensions: 38 × 22 mm
• Mounting holes: 2 × 3.2 mm