TMDS442: unused input terminal

Yasushi Fujiwara

Part Number: TMDS442

Hello experts,

Regarding an answer of a following thread, would you clarify what is different between unused input terminal and left open (it has unconnected connector)? I suppose it seems there are same condition.

https://e2e.ti.com/support/interface/f/138/t/333657?tisearch=e2e-sitesearch&keymatch=TMDS442

Best Regards,
Fujiwara

over 6 years ago

0 David (ASIC) Liu over 6 years ago

TI__Guru**** 185551 points

Fujiwara-san

Unconnected connector means TMDS422 input is connected to the the connector, but there is no cable attached at the connector.

Unused input terminal means TMDS422 input is floating, not connected at all.

Thanks

David

0 Yasushi Fujiwara over 6 years ago in reply to David (ASIC) Liu

TI__Genius 12725 points

David-san,

Customer wants to left open (floating) the unused input terminals. The datasheet stated that "An unused input channel can be externally biased to prevent output oscillation". If customer left open the unused input terminals, TMDS output will oscillate? I want to know an external biasing for unused input terminal is just recommendation or it is mandatory. Which is TI suggestion?

Best Regards,
Fujiwara

0 David (ASIC) Liu over 6 years ago in reply to Yasushi Fujiwara

TI__Guru**** 185551 points

Fujwara-san

I would recommend following the datasheet. Since TMDS input pins are not failsafe circuits. The complementary input pin is recommended to be grounded through a 1-kΩ resistor and the other pin left open.

Thanks

David

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TMDS442: unused input terminal