Parallel connection approach ADM3057EBRWZ

Hello Basit,

   I'm assuming that you're intending to provide a 2nd set of bus connections to facilitate a daisy-chain connection for the bus with terminals for the left and right sides of the bus (with respect to the device).

   You should not repeat the terminating network, at most there should only be 1 terminating network present and it would only be present if the node was at one end of the bus.  This would topologically mean that one set of terminals was left unconnected.

   Also note that repeating the TVS diode will add additional capacitance to the bus with minimal value and I'd suggest removing one.  Depending on the end application, the capacitance from the 2nd TVS diode may not cause issues, but...

Eric

Thank You ericb. You meant to say to connect it like the following:

Hi Basit,

  Yes, your new circuit is how I would suggest structing the node's connections to two physical bus segments of the same electrical bus.

   Note that the termination network should only be present when the node is connected to one of the two terminal ends of the physical bus and in this case there would only be connections to one set of the bus terminals.  In my experience, nearly all of the field use cases where both sets of terminals would be utilized should not have the termination network connected/present since this use case implies that the node is in the middle of the bus.  Thus, I would suggest having a means for the person installing/commissioning the equipment in the field/end-use location to be able to determine, at the time of installation, if the termination network should be present or not based on that particular node's final installed location in the system.  This could be managed by having the determination happen at the factory with 2 different SKUs and the installer selects the correct one to install or perhaps you require the installer to rework the board to remove the network as an installation step.  These options do have drawbacks for the installer/end customer by requiring additional inventory and/or project risk of having the incorrect mix of units and delaying while getting more of the correct units or requiring a higher level of skill on the part of the installation tech - reworking a PCB is a different skill set from being able to physically install equipment.  Adding a switch or jumpers to enable/disable the termination does increase cost, but in my opinion is a more field-installer friendly option which may justify the increased cost/complexity.

Eric