3.3V LVDS to 1.8V LVDS Buffer with Vos for 1.8V Spec

Hello All,

www.ti.com/.../cdcun1208lp - something like that will work but I only need 4 LVDS outputs - not 8.

Thanks,
John W.

Hello All,

For the CDCUN1208LP - is it OK to have Vdd=3.3V and VDDox = 1.8V?

Thanks,
John W.

Figure 2 implies the Vddo can be different voltages and page 20, Configuration of Output Type (OTTP) seems to
establish this.
73,
Timothy

Hello Timothy,

If my input to the CDCUN1208LP is 3.3V LVDS - do I have to supply the reference voltage of 1.2V DC to the input? I see that on the EVM - but maybe that is only for SE inputs?

Thanks,
John W.

Hi John,

figure 17 from the datasheet shows the configuration for differential input types. For LVDS you only need a 100Ohm termination.

Regards,
Julian

Hello Julian,

Why is the attached necessary then - this is from the eval board schematic.

Thanks,

John W.

p11-1208lp-eval-board.pdf

Suppling a bias/termination voltage is necessary for LVDS, if your input signal is AC coupled. A DC coupled LVDS signal can be connected directly as shown in the datasheet.

regards,
Julian

Julian,

OK - that wasn't crystal clear to me - wondered why that was there.

Another question - is the min. frequency for this part 8 kHz?
If it is DC-coupled - will it pass DC? In this case meaning, will the
outputs just drive low and/or high?
Sorry for all of the questions - trying to satisfy a customer req.

Thanks!
John W.