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MAX3232E: Can one MAX3232 support two independent RS-232 devices simultaneously?

RAYAN SAYED
Prodigy 30 points

Part Number: MAX3232E
Other Parts Discussed in Thread: MAX3232

I am designing a system using the MAX3232 RS-232 transceiver and would like to clarify its channel capability.

The MAX3232 has two transmitter channels (DIN1/DOUT1, DIN2/DOUT2) and two receiver channels (RIN1/ROUT1, RIN2/ROUT2).

My requirement is to connect two independent RS-232 devices to a single MAX3232, with each device having its own independent UART communication channel from the MCU.

For example:

MCU UART 1 ↔ MAX3232 Channel 1 ↔ RS-232 Device 1

MCU UART 2 ↔ MAX3232 Channel 2 ↔ RS-232 Device 2

My questions are:

  1. Can a single MAX3232 be used to interface with two independent RS-232 devices in this way?
  2. Can both channels operate independently and simultaneously?
  3. Is there any limitation or interaction between Channel 1 and Channel 2 that I should consider?
  4. For the charge-pump capacitors, should I use the recommended capacitor value from the datasheet, or is there any reason to increase/decrease the value when both RS-232 channels are being used simultaneously?
  5. Does using both channels simultaneously have any impact on the charge-pump output voltage or capacitor requirements?

I understand that the MAX3232 provides two separate drivers and two separate receivers, but I would like to confirm whether this architecture is valid for two independent RS-232 connections and whether any changes to the charge-pump capacitor values are required.


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  • 0
    TI__Intellectual 2260 points

    Hi Rayan,

    RAYAN SAYED said:
    • Can a single MAX3232 be used to interface with two independent RS-232 devices in this way?
    • Can both channels operate independently and simultaneously?
    • Is there any limitation or interaction between Channel 1 and Channel 2 that I should consider?

    As long as you remain within the datasheet spec for inputs you should be fine to operate it in this way. Nothing extra outside of the datasheet that needs to be considered.

    RAYAN SAYED said:
    For the charge-pump capacitors, should I use the recommended capacitor value from the datasheet, or is there any reason to increase/decrease the value when both RS-232 channels are being used simultaneously?

    Stick with the recommendations in the datasheet.

    RAYAN SAYED said:
    Does using both channels simultaneously have any impact on the charge-pump output voltage or capacitor requirements?

    No

    -Ethan White