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ADV7281 STB Protection Network

Question asked by BenD Employee on Jun 6, 2014
Latest reply on Jun 9, 2014 by Rob.Analog

I am planning to use the ADV7281-M in an application in which the differential analog signal levels do not require attenuation in the differential input network. I'll refer to Figure 12 in the ADV7281 datasheet, which shows the suggested Differential Input Network. Would it be advisable to remove the 430 ohm resistor from the network and keep the 1.3k resistor to limit current through the 100nF cap during a STB transient event? Or is it necessary to include a larger resistor in place of the 430 ohm resistor, in order to provide a transient current path to ground while creating very little attenuation? It's not clear to me whether the current through the caps during a transient STB event is a reliability concern for the ADV7281. If that is not a concern, would it be okay to remove the 430 ohm resistor and replace the 1.3k with a short?

 

I suspect that the transient current is not a concern, but I want to be certain before I change the protection network. In short, what Differential Input Network would you recommend when there is no need for attenuation?

 

Thanks,

Ben

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