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MAX3243E: receiver input resistance when FORCEOFF# = 0

Tamas Ledeczi
Intellectual 390 points
Part Number: MAX3243E

I'm looking for an RS232 transceiver from TI where I can switch the input resistance of the RS232 receivers between the typical 5kOhm and high-impedance. I don't necessarily need a dedicated control pin for this, what I need is a high-impedance RS232 receiver input when the chip is FORCED OFF, and the typical 5kOhm input resistance when the chip is enabled. Something similar the MAX3322E (or MAX3323E) can offer. I used the MAX3243E in a variety of designs, but based on the datasheet I don't think this part supports this feature. Please advise and suggest a part with this feature included, number of Tx/Rx per part doesn't matter.

Thanks:

Tom Ledeczi

  • 0
    TI__Mastermind 25705 points

    Tom,

    Unfortunately we don't have a RS232 transceiver that can switch the RIN pin to high impedance. Actually most of our RS232 receivers don't have enable, since the RX takes very small power. Can you give some detail why you need to do this in your system? You might be able to implement this function by adding external switches. If you do so, please choose the components can work with RS232 voltage range. Please let me know if you have more questions.

    Regards,

    Hao

  • 0 in reply to Hao L
    Intellectual 390 points

    Hi Hao,

    Thank you very much for the quick feedback. The reason of my question is that I'm planning to implement multidrop application, where I have to switch all but one receivers to high-impedance input to keep the standard typical 5kOhm load the transceiver has to cope with. I found just MAXIM provides this feature at some RS232 transceiver parts. Finally, I decided to use simple relays for the job.

    Thanks again for your inputs!

    Best Regards:

    Tom