• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 2 answers
  • Subscribers 35 subscribers
  • Views 158 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

MAX3232: Datasheet Assistance

TI-CSC
Genius 14885 points
Part Number: MAX3232


Hello E2E Experts,

MAX3232 3-V to 5.5-V Multichannel RS-232 Line Driver and Receiver With ±15-kV ESD Protection datasheet (Rev. O)

I am looking into this IC for one of my designs but I have some questions that the datasheet doesnt answer. I am looking for the behaviour of the outputs when VCC is 5V. There is only information and graphs when VCC is 3V3. Specifically the application curves, typical characteristics, and parameter measurement information for VCC = 5V would be great. 

If I have a 3V3 logic uart input going into the device, would it be able to communicate fine if the IC VCC is 5V?

  • 0
    Guru 319270 points

    VCC determines the logic I/O voltages. You must use 3.3 V.

  • 0
    TI__Guru* 77791 points
    TI-CSC said:
    am looking for the behaviour of the outputs when VCC is 5V. There is only information and graphs when VCC is 3V3. Specifically the application curves, typical characteristics, and parameter measurement information for VCC = 5V would be great. 

    You can estimate the Ron of the Dout driver but using the electrical parameters for Voh and Vol. 

    TI-CSC said:
    If I have a 3V3 logic uart input going into the device, would it be able to communicate fine if the IC VCC is 5V?

    The recommended operating conditions table shows that ViH and ViL for the TTL inputs are 2.4V and 0.8V when Vcc is 5V. So technically you you can have Vcc at 5V and apply 3.3V logic to the DIN pins.

    -Bobby

  • 0 in reply to BOBBY
    Prodigy 10 points

    Hey Bobby, 

    Thanks for the reply, wouldn't Rout be at 5v logic with Vcc at 5V? Also does the internal charge pump output 5.5V? How would you get the driver output to get to 13.2V?

  • 0 in reply to Max
    TI__Guru* 77791 points
    Max said:
    Thanks for the reply, wouldn't Rout be at 5v logic with Vcc at 5V?

    That's correct. You would need to either translate it down with a level translator device or you could try to do this passively with a resistor divider.

    Max said:
    Also does the internal charge pump output 5.5V?

    Only on the RS232 side not the TTL (Rout) side.

    Max said:
    ow would you get the driver output to get to 13.2V?

    None of our RS232 devices will output this kind of voltage. The highest would be +/-9V unless you provide your own +/-13V source.

    -Bobby