Problem with MAX232 capacitors value

Discussion in 'General Electronics Chat' started by anhnha, Apr 21, 2012.

  1. anhnha

    Thread Starter Active Member

    Apr 19, 2012

    I took 2 chips MAXIM MAX232 for my project but there is a prolem when I check MAX232 for test.I have tied capacitors like that attached in this post BUT i do not used capacitors like datasheet.All capacitors is 10uF rather than 1uF like datasheet.When i tied 11 pin(Tin with TTL level) to GND and then measure the voltage at 14 pin(232 output) I have read a value is 4.6V.I think It should be at -10V (232 standard).I have try 2 chips but they are same, with wrong conversion.Do you know this chip is not work?OR this is the problem of the capacitors that I had used.Do i really need to used all 1uF capacitors like datasheet.Could you expain me the value and how these capacitor is used.Thanks.
  2. Markd77

    Senior Member

    Sep 7, 2009
    MAX232 inverts so you should expect around +7V (typical value from datasheet) on the output if you ground the input.
    Measure at pins 2 and 6, they should be +10V and -10V relative to ground.
    Check the polarities of the capacitors.
    If that fails get the right capacitors, they are a dime a dozen.