LTC4354 APPLICATION FOR ADAPT TO UNUSED FUNCTION

Dear managers,

I designed with the LTC4354 to sum up the two -48V PATHs coming from the PSE.

However, there is an effect of AC noise in classfication detect at the PD block.

So, I decided  to ususe DA,DB pin by processing and it connected with GND. after connecttion, PD detection is ok.

Please tell me about the functions and effects that cannot be used when DA and DB are connected to GND.

Please let me know if there is a proper solution for improving issue.

What are the expected functional limitations?

The following is expected. 1. MOSFET out of control 2. Limit power switching function 3. Limitation of fault detection function

Could you please advise me?

additional test informations as below.

Test condition)

VA and VB are each supplied from two PoE PD outputs. I would like to OR-ing the two outputs through the LTC4354.

failure case)

If DA or DB is connected to VA, VB through a resistor.

Among the PDs in the pilot, the polarity of the VSS was corrected in the PD that was classified first.

Therefore, a Classification Fail occurred later because LTC4354 affected PD in classification.

cleared case)

Solved the problem by connecting to VSS like feeling in Datasheet to unused of the DA and DB.(DA and DB -> directly connet to VSS)

Thanks and regards,

Daejung.kim