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I have a two diffrent boards. One of the board is send the SoC and other things to Charger Board. While charging progress starts I want to isolate this to device because battery ground is isolated to MCU ground. When I connect this board together I will connect MCU ground to Battery ground. Sender board is powered by this battery. While I am researching I see MAX3250, It is isolated RS232 Driver IC. At sender board I use MAX232, Can I do MAX232 -> MAX3250 combination? I don't want to change Sender board MAX232 to MAX3250 because MAX3250 is too expensive. How can I implement this to system. Basically 2 board has a MCU with diffrent grounds and between them there is a 2 RS232 IC to communicate. MAX3250 datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/MAX3250.pdf Images reference is above datasheet.

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Schematic of system: (Additional components are didn't given (C1,C2,C3,C4 caps etc.))

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  • \$\begingroup\$ Why would you use isolated RS232 over isolated RS422/RS485? Might as well send Maxim a blank check... "please bill me ridiculous amounts of money". \$\endgroup\$
    – Lundin
    Commented yesterday
  • \$\begingroup\$ I didn't work with rs422/rs485 protocols before. I am building Charger board. Other board is already have a MAX232. Thats why I am looking for something to cooperate with Data Sender BOARD. \$\endgroup\$
    – MSB
    Commented yesterday
  • \$\begingroup\$ It's not a protocol, it's a hardware layer standard. Just like RS232 is not a protocol but a hardware layer standard - just an older and less rugged one. And it seems like 1000pcs of MAX3250 will cost you about as much as a decent car. \$\endgroup\$
    – Lundin
    Commented yesterday
  • \$\begingroup\$ Thanks for reply. I find a ISO7721-Q1 dual chanel isolator from TI. MAX232 and ISO7721 total 2.9 USD. Not sure is it work or not I am looking for it. Much more good compared to price of car :) \$\endgroup\$
    – MSB
    Commented yesterday
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    \$\begingroup\$ Why do you really need isolation? Are you sure, or does it just seem like "a good thing"? What problem is isolation solving for you? \$\endgroup\$ Commented yesterday

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