SN65LVDS049 - Open fail safe

Hirotaka Matsumoto

Other Parts Discussed in Thread: SN65LVDS049

Hi all

Would you mind if we ask SN65LVDS049?

On the datasheet Figure 8. Open-Circuit Fail-Safe of the LVDS Receiver, it shows internal bias resister about 300kohm.
Since VIT- is -100mV.(-100mV < VID < 100mV : ROUT X), we guess that RIN- has to connect to GND internally, right?
Is our recognition correct?

Kind regards,

Hirotaka Matsumoto

over 9 years ago

0 Elias Villegas M. over 9 years ago

TI__Guru* 76130 points

Hello,
I'm sorry but I don't understand your question, can you explain what do you mean by "RIN has to connect to GND internally ?
Figure 8 show the fail-safe feature when there is no LVDS input, how does that is related to connect Rin to GND?
Regards

0 Hirotaka Matsumoto over 9 years ago in reply to Elias Villegas M.

Guru 27585 points

Elias san

We are sorry that our explanation makes you confuse.

-In case of Open : Rout is High
-If Rout is high, it will be VID > +0.1V(VIT+=0.1V)
-So, that's why if RIN+ connects to pull up internally, RIN- connects to pull down internally for VID > +0.1V.

Is our recognition correct?

Kind regards,

Hirotaka Matsumoto

0 Hirotaka Matsumoto over 9 years ago in reply to Hirotaka Matsumoto

Guru 27585 points

Elias san,

We guess that your days are so busy, however could you give us the reply?
We appreciate for your help always.

Kind regards,

Hirotaka Matsumoto

0 Elias Villegas M. over 9 years ago in reply to Hirotaka Matsumoto

TI__Guru* 76130 points

Hello,
I think I understand your question, the answer is No, Rin- is not internally connected to GND.
Rin+ will compare the input with +100mV and Rin- with -100mV, if the input signal is not within -100mV to 100mV then the device will use the 330K pull-ups to drive the AND gate shown in Figure 8 and thus providing a high level on the output.
Regards

0 Hirotaka Matsumoto over 9 years ago in reply to Elias Villegas M.

Guru 27585 points

Elias san

OK, I can understand.

Regards,

Hirotaka Matsumoto

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SN65LVDS049 - Open fail safe