LTM2882 - Schematic Review

With the exception of T2IN which appears to be left floating and should be tied to either VL or GND, what is shown in your schematic looks OK. 

As mentioned in the datasheet, I'd suggest that the bulk capacitors C1 and C3 be selected with a higher ESR to help with damping of the supply and C2 should be a low ESR cap. 

Be sure to confirm that the voltage ratings for the barrier capacitors C4 and C5 are sufficient for your application's isolation requirements.

Be sure to follow the PCB layout and assembly guidelines which are referenced on the part's web page (link repeated here: uModule Design and Manufacturing Resources)

Hello! Thanks for your reply. See updated schematic per the datasheet. This would be the same circuit we would have on both ends (both PCBAs):

In my previous schematic - DE and DOUT were tied together, but after further review - these should be tied to VCC - correct?

I have tied T2IN with a pull down:

Could you do another glance over of the schematic? Thank you.

It depends on what your design goals are.

What you drew previously was perfectly fine IMO.  Connecting DE to DOUT allows you to control the drivers by the setting of DIN.  Having DIN pulled to its +3v3 VL supply will basically have DE always active when the part is operational.  you could also run the DE to a controller GPIO with an optional pull-up; etc. this would give you the potential in the future to turn off the driver if you wanted (e.g. for a lower power mode of operation which may or may not be valuable in your application).

Connecting DE to its associated supply is also OK.  In this case, it would be the unlabled net with the VCC2 pins and C3.  Do NOT use +3V3 since that is on the other side of the isolation barrier and this connection effectively negates the isolation barrier (and likely could cause EOS damage to the part).

Connecting DOUT to any supply is not OK.  Its a driven output and if its state is not high-Z or VCC2, it will try to pull VCC2 down to GND2.  DOUT should be left floating if you're not using it.

Hello! Many thanks for your reply.

I have updated the schematic per your recommendations, we will tie DE and DOUT together and allow DE to control the driver by always being pulled to 3V3 (always operational).

Looks ok now?

This looks OK connection wise. 

I note that over the evolution of the schematics, the names of the GND/reference nodes have changed.  As long as things are consistently labeled, the electron's won't care what you call the nodes.  That being said, calling the node connected to B1-B6 "ISO_GND" is atypical and could be suggestive of a possible error in the overall schematic.  Or not - it may be perfectly logical and correct in your use case/application, but I'm calling this out to make sure you've verified that you've got all of the nodes consistently and correctly labeled.

Hello,

Thanks for this - The "ISO_GND" is because this 3V3 and ISO_GND is separated from the input voltage / GND, but yes - I can see your point and noted. 

Appreciate your support!

Hello Eric,

Do you recommend the isolated GND from the VCC2 side tie back to input / chassis gnd via 100-ohm resistor or similar?