Hello
I read from GPIO_Revision 2.0 8.5.4.2 TMDS General Routing Guidelines
single end impedance control should be 60 ohm, why is 60 ohm not 50 ohm?
thank you
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Hello
I read from GPIO_Revision 2.0 8.5.4.2 TMDS General Routing Guidelines
single end impedance control should be 60 ohm, why is 60 ohm not 50 ohm?
thank you
Hi,
I've pinged documentation team and they said 60 ohm is correct.
By the way, HDMI spec doesn't specify the single-end impedance. It only specifies the differential impedance of 100 ohms.
Regards,
Stan
Locust,
From 'HDMI Board Design and Layout Guidelines' section of the TDA2x Data Manual:
"The TMDS differential signal traces must be routed to achieve 100 Ohms (+/- 10%) differential impedance
and 60 ohms (+/-10%) single ended impedance. Single ended impedance control is required because
differential signals can’t be closely coupled on PCBs and therefore single ended impedance becomes
important."
I think there is a misunderstanding between single ended impedance and differential impedance, in your original question.
-Colin
-Colin