What is the correct PCB design impedance to use for an LPC4330 GPIO/SGPIO output pin?

[timhutcheson]

In particular, I' designing a high speed SGPIO 8 lane transfer pipe between two LPC4330 and am interested to know if I can avoid adding 33-50 ohm series resistors for a length of less than two inches between processors or not.

I was not able to find any impedance information in the literature available but assume that no source resistors a re built into the device.  Is that true?

Tim

[kerryzhou · Accepted solution]

Hi Tim Hutcheson,

    Thank you for your interest in LPC product, I would like to provide service for you.

   As I know, the GPIO/SGPIO don't have the specific PCB layout impendance requirement. If the wire length is less than two inches, I think you don't need to add 33-50 ohm.

   Actually, we have an application note: SGPIO camera module design using LPC4300

       You can refer to the application note, there has a PCB board which is drawn by eagle design.

 

You can find the SGPIO layout also don't have the resistor. About the wire wide, you also can refer to this board, it is 8mils.

Wish it helps you!

If you still have question about it, please kindly let me know!

Have a great day,
Kerry

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