Dear Sir,
I found some topic about this, the TI fae told the TMDS181 only support dc-coupled input, doesnt support ac-coupled input!
In fact ,the TMDS 181 function diagram , there are pull-up resisters (50 ohm) connected with Vbias. so, TMDS181 shall support ac-coupled input.
Is it right？
Hi,
HDMI uses current drive on the source side to develop the low voltage differential signal at the sink side. The termination voltage on the sink side sets the high voltage level of the differential signal. The low voltage is set by the current at the source and the termination resistance at the sink.
A compliant HDMI source should not drive the TMDS line exceeding the conditions being set in Table 4-23 of the HDMI spec.
In case of DC coupling, actually input voltage never exceed recommended spec if user compliant HDMI spec.
But in case of AC coupling with TMDS181, input voltage become 3.3V + Vswing. So input voltage exceed TMDS181 absolute spec and will damage the TMDS181 input.
Thanks
David.
Hi,
Please see section 6 for the absolute max rating on the differential input voltage.
Thanks
David
