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LM74700-Q1: Parallel to LM74700 ideal diodes

Part Number: LM74700-Q1

Can two LM74700 devices operate in parallel?  (not two FETs being driven by one LM74700, but two LM74700 circuits). 

In an application where this is being done and7 tested against a reverse polarity input, sometimes one of the parallel devices fail.  

  • Hi Mark,

    LM74700 is an ORing controller which can support external FETs with any desired amount of current carrying capability. Can you please clarify the need for paralleling multiple ORing controllers?

    Best Regards

    Divyanshu

  • Two LM74700 devices are in parallel to share the current.  I understand that this can be done with a single LM74700 and multiple FETs, but the present design uses two LM74700 devices and the customer is trying to understand if this arrangement is causing reverse polarity issues (like a race condition between the two parts). Failures do not always occur under test, only occasionally. When a device fails, the LM74700 shows Anode-Cathode shorts, but the FET survives.   

  • Hi Mark,

    During reverse input polarity, gate and anode pins are shorted internally. Therefore, during reverse polarity the two gate pins will be shorted together as the anode is the same for both the devices. This may cause one of the devices to fail due to current flow into the gate pin of one of the devices. Since the customer is anyways using multiple FETs to carry the load in this scheme also. there seems to be no advantage of using multiple controllers in parallel. Please recommend the customer to use multiple FETs with one controller, which would give the customer advantage in terms of reliability during RPP, cost and space, with the same protection features.

    Best Regards

    Divyanshu