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Userrr
Joined: 09 Jul 2004 Posts: 40 Location: Europe
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Uncoupling RS232 |
Posted: Fri Dec 24, 2004 9:23 pm |
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Please help me find easy opto-uncoupling or inductor.
I found ADUM1402 Digital Isolator with 5V supply and current - 1ma per channel. I think use this without max232 and use supply from PC.
but how make 5V from 13V - q? to convert TX,RX, and power?
How I can do this?
Thanks! |
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Sandman
Joined: 26 Jan 2004 Posts: 15 Location: Kiruna, Sweden
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Re: Uncoupling RS232 |
Posted: Sat Dec 25, 2004 10:40 am |
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The ADUM1XXX chips are very nice and works well. Just keep in mind that the supply voltage on the primary and secondary side should be independent (It works in some sense with the same supply on both sides, but I have run in to interference problems when this was used.).
Also keep in mind that the digital isolator like ADUM is NOT a line driver. It means that the output current from the circuit is rather small and should only be used for onboard circuits, or with short, shielded wires since the line will be very sensitive to attenuation. The system will also be more sensitive to disturbances like EMI when no driver is used.
Driver protocol like RS232, 422 and 485 (etc.) are developed for this reason.
If you are using the PC power supply you will have 5V available. Why use 13V? If your plan is to communicate with a PC I strongly recommend you to use RS232 (keeping KISS in mind ). |
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kender
Joined: 09 Aug 2004 Posts: 768 Location: Silicon Valley
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Posted: Sun Dec 26, 2004 4:54 pm |
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Also Maxim makes MAX3250, which integrate isolation and RS-232 line driver.
Nick |
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