Timeline for Impedance matching in 2-layer FR4 board
Current License: CC BY-SA 4.0
11 events
| when toggle format | what | by | license | comment | |
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| Sep 13, 2022 at 4:18 | comment | added | Eric Matevosian | @VoltageSpike I've made an edit to the main question, and marked the resistors that I mentioned before. I've read somewhere that the series resistors can help to adjust the impedance thing. but I did not get why the resistors are only on some data lines and others dose not have them. which signals are more sensitive? the signals between PHY and MAC , or between PHY and Magnetics ? | |
| Sep 13, 2022 at 4:14 | comment | added | Polynomial | @VoltageSpike I've not had any issues with their soldering, but admittedly I've only done about 15 assembly jobs through them. (Edit: Actually I did have two USB Micro connectors with dry joints when I did a a panelised batch of 200 assembled boards, but honestly I'm ok with that level of reliability for the price I paid) | |
| Sep 13, 2022 at 4:12 | comment | added | Eric Matevosian | thank you @Polynomial for your recommendations | |
| Sep 13, 2022 at 4:12 | comment | added | Eric Matevosian | @VoltageSpike thank you for your recommendations, In this case I have to go with 2layer. as the customer wanted! it is possible the project to be canceled if we go on 4layer board. | |
| Sep 12, 2022 at 21:03 | comment | added | Voltage Spike♦ | I've been not too happy with jlcpcb's soldering finish on my last batch of boards from them. | |
| Sep 12, 2022 at 19:07 | comment | added | Polynomial | @EricMatevosian JLCPCB does 4-layer boards very cheaply, with two choices of impedance controlled stackup (7628 and 3313 prepreg) at no extra cost. They've got full stackup info and an impedance calculator on their site. They're very popular in the hobbyist community due to their low cost and reliable quality. | |
| Sep 12, 2022 at 15:20 | history | edited | Voltage Spike♦ | CC BY-SA 4.0 |
added 320 characters in body
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| Sep 12, 2022 at 15:18 | comment | added | Voltage Spike♦ | Try PCBway out of china, you will have a very hard time doing this on a 2 layer board. Again, you need to decrease the thickness of the board and or increase the dielectric. I'd give you some numbers but they'd be meaningless because you need to talk to your boardhouse and see what they can produce. The RMII needs a continuous ground plane, this will be hard or impossible to achieve on a two layer board | |
| Sep 12, 2022 at 7:03 | comment | added | Eric Matevosian | May I use series termination resistors (about 10ohms I saw in some designs) to the job of impedance matching? | |
| Sep 12, 2022 at 6:49 | comment | added | Eric Matevosian | thank you @Volrage Spike for your time.. oh.. the 4layer board is not that common here yet and the prices are more than 4X of normal 2layers board. is it possible to handle this kind of project with 2layer boards? | |
| Sep 12, 2022 at 6:10 | history | answered | Voltage Spike♦ | CC BY-SA 4.0 |