DS90LV031A: Works with DS90LV032A at ac-coupling

Kazuhiko Hirano

Part Number: DS90LV031A
Other Parts Discussed in Thread: DS90LV032A

Hello,

My customer plans to use DS90LV031A and DS90LV032A to transmit and receive 12.624Mbps CMI (Code Mark Inversion) code data having only ac component via 100ohms/0.5m differential cable as follows.
Do DS90LV031A and DS90LV032A work with ac-coupling like this?

Best regards,

K.Hirano

over 2 years ago

0 David (ASIC) Liu over 2 years ago

TI__Guru*** 139405 points

Hirano-san

For AC coupling between LVDS, please refer to this app note for the implementation,https://www.ti.com/lit/an/slaa840/slaa840.pdf.

The data must be DC balanced in order to use the AC coupling.

Thanks

David

0 Kazuhiko Hirano over 2 years ago in reply to David (ASIC) Liu

TI__Genius 11613 points

David,

Thank you for your response.

But just in case, le me confirm some more.

Q1:
In the document, the capacitors for ac-coupling are located driver side, not receiver side.
But can they be both side, driver side and receiver side?
Or they must be only driver side?

Q2:
Does DS90LV032A need DC-bias circuit as Figure 3 to 5 in the document?
Or DS90LV032A has wide common mode input voltage range, and Figure 6 can apply?

Best regards,

K.Hirano

+1 David (ASIC) Liu over 2 years ago in reply to Kazuhiko Hirano

TI__Guru*** 139405 points

Hirano-san

1. You can AC coupling both the driver and the receiver, but this will reduce the total effective AC coupling capacitance. For example, with 0.1uF cap on the driver and 0.1uF on the receiver, the total capacitance is 0.05uF. Depends on the data density being transmitted across the LVDS interface, you may have DC wandering issue.

2. The LV032A input common mode voltage is 1.2V, so you still need to use external biasing network.

Thanks

David

0 Kazuhiko Hirano over 2 years ago in reply to David (ASIC) Liu

TI__Genius 11613 points

David,

I see, thank you for your responses.

Best regards,

K.Hirano

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DS90LV031A: Works with DS90LV032A at ac-coupling