Speed issue

TCP/IP Chip W5500
1

Hi ,
I am facing speed issue in my new design, its detecting 10Mbps after some time its detecting 100mbps / after multiple power ON its detecting 100Mbps( link was not stable every time mostly its speed detecting 10mbps). may i know the what is the exactly issue in my design.

below path for schematic

2

Hi
your schematic looks OK.
could you share your PCB gerberfile?

3

thank you for your replay.
Please follow below link for gerber files.

4

Could you send it to me in a Gerber file format rather than a PDF?
Cause viewing the gerber file as a PDF makes it harder to find problems.

5

Thank you,
Please find the below link :
PCB FIle : PCB
PCB Schematic : SCHEMATIC_DRAWING

6

Try to set W5500’s PMODE pin with 100BT Full-duplex and test it again.
If not solved, refer to the HW design points below and supplement them

Keepout GND plane under the Lan transformer(in your case under the RJ45)

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increase RJ45 Center tap’s trace width

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image950×648 76.1 KB

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image436×550 30.7 KB

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image501×611 37.8 KB

Make sure the power source for the W5500 is stable.

All of W5500’s GND pin is connected GND through only few vias it looks unstable.
Reinforce W5500’s GND

7

Okay Thank you Jaden for your valuable suggestions,
Ground plane routed in 2nd layer.

8

You did not say if the problem persists if you connect to different devices at another end of the cable. I see you confused RX/TX at the jack, may not be a big problem because transformer is symmetrical, but will force endpoint device to function in cross-over mode. You are missing formal connection of C19 on the circuit diagram, but on the board it seems to be connected properly. Crystal is out of tolerance specification - you use 50 ppm instead of max 30 ppm. You did not separate digital and analog circuits with simple ferrite bead-based filter. Layout looks strange, in particular why you have put power loops on the top and bottom layers when you have power and ground planes. Power supply layout is not good - datasheet says to put ground vias, and you put then far away from the coil and Cout. You have put 0R resistors wherever possible - do you know they also have power rating? Are you sure R89 feels good by itself, and makes circuit after it feeling well?
All these will add to the overall quality of operation.

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