DS92LV2422: impedance match circuit

maga75

Part Number: DS92LV2422

Hello All,

We are going to use DS92LV2422 in our design. LVDS video will be come from source via 140 Ohm cable. Could you recommend impedance match circuit for that case, since CML diff input of DS92LV2422 is 100Ohm (100Ohm internal termination resistor).

Maxim

over 6 years ago

0 Ikechukwu Anyiam over 6 years ago

TI__Mastermind 35130 points

Hi maga,

It would be better to just switch to a 100 ohm cable. Since the differential traces on your board also need to be 100 ohm, I believe any passive component circuit you add would change that impedance.

Regards,
I.K.

0 maga75 over 6 years ago in reply to Ikechukwu Anyiam

Prodigy 115 points

Hello I.K.

Thank you for the respond!

Yes, we are going to use passive impedance matching circuit.

Please see below. The only thing - I thinking about resistor Rc value. Your thoughts?

Maxim

0 Ikechukwu Anyiam over 6 years ago in reply to maga75

TI__Mastermind 35130 points

Hi Maxim,

I don't think you need that many components like in your circuit. You can probably get rid of all of those resistors, and just add a 20 ohm resistor on each line after C1 and C2, as close to the deserializier input pins as possible. You can also reference some of the techniques used in this article for impedance matching: www.electronicdesign.com/.../back-basics-impedance-matching-part-1

But again, the best and simplest thing to do would be to just use a 100ohm cable.

Regards,
I.K.

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DS92LV2422: impedance match circuit