Max485 Design Considerations

Thread Starter

nadeemyj

Joined Jun 9, 2020
1
Dear All,

I am little confused on how to go with my max485 design.

I have a Device that can only communicate through rs485, with voltage levels of around 0to3 v according to the scope.

My mcu can only work with serial ttl, hence i need a max485 converter. However, I am a little confused about what kind of protection is needed if any. I was thinking of using the reference design I found on the net. But when I research it I was confused about whether I really need all those components. As my MCU will be on the same PCB as the Max 485, would I need the Schmitt hex inverter. As there would be very little noise..

Furthermore I saw some other designs use a Quad-Channel, 2.5 kV Isolators with Integrated DC-to-DC Converter Adum5042 isolator, not sure why they used this? Is it needed?

I am more concerned about overcurrent protection from the rs485 a and b side, and transient current. Furthermore, reliability to make sure the rs485 doest fail. We plan to run it at a very reasonable speed of 115kbps max
 

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