SN65LVDS33: Single line input

amnon pomerants

Part Number: SN65LVDS33

What will happen in case one of the LVDS input line is now disconnected (or the POS [A] or the NEG [B] ) and left floating

while the opposite pin keeps working as usual?

Will the receiver still present the proper value (maybe due to the "Attenuation Network" a floating line will be driven to 3.3V*250K/ (250K + 60K) = 2.66V and thus when the opposite proper signal toggles between 3.3V and 0V the required difference between POS and NEG is kept...??)

If the above is true, when I start feeling and kind of problem due to the disconnect net ?

Thanks

Amnon

over 5 years ago

0 Ikechukwu Anyiam over 5 years ago

TI__Mastermind 35130 points

Hi amnon,

The receiver inputs are high impedance so the line that is still connected should still have around a 350mV swing (though distorted). This is not a proper input for the device, so a proper output cannot be guaranteed.

Regards,

I.K.

0 amnon pomerants over 5 years ago in reply to Ikechukwu Anyiam

Intellectual 780 points

Hi I.K

Thanks for the prompt answer.

Can you elaborate please of how did you calculated the value of 350m swing

and where do you see in the datasheet that this is not a good enough swing ?

Thanks again

Amnon

0 Ikechukwu Anyiam over 5 years ago in reply to amnon pomerants

TI__Mastermind 35130 points

Hi Amnon,

The 350mV is from a LVDS driver. Please review these training videos: https://training.ti.com/node/1139372

Regards,

I.K.

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SN65LVDS33: Single line input