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Electronics => Projects, Designs, and Technical Stuff => Topic started by: ricko_uk on November 25, 2024, 12:14:56 am

Title: MIPI-DSI immunity to switching noise?
Post by: ricko_uk on November 25, 2024, 12:14:56 am

Hi,
because of PCB layout constraints I have to place a synchronous-type switching regulator (24V in to 3V3 out running at 2A) next to the MIPI-DSI connector.

The inductor is fully shielded and all the power-path traces are as short as they can be (literally 2-3 mm long).

How immune is MIPI-DSI to switching noise? Is it ok to place the switching regulator right next to it?

Thank you

Title: Re: MIPI-DSI immunity to switching noise?
Post by: uer166 on November 25, 2024, 12:30:00 am

Looks like they're ~50 Ohm SE impedance diff pairs, so the usual applies:

Don't cross GND slots, reduce crosstalk by keeping the offenders away by 5-10 prepreg heights, either don't flood top layer with GND, or if you do, stitch it every 1/10th wavelength of the signal in question, etc etc.

It doesn't seem particularly sensitive, just like most high-speed controlled impedance interfaces.

Title: Re: MIPI-DSI immunity to switching noise?
Post by: ricko_uk on November 25, 2024, 02:25:03 am

Thank you @uer166 :)

Title: Re: MIPI-DSI immunity to switching noise?
Post by: Pbtz on November 26, 2024, 09:52:10 am

In my experience MIPI is fairly robust in general. I've made it work over 10-inch bodge wire.

Title: Re: MIPI-DSI immunity to switching noise?
Post by: ricko_uk on November 26, 2024, 04:48:18 pm

Thank you Pbtz.

At what speeds did you do that?