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MAX3232: Recommendation range of decoupling capacitor for Vcc

Ryuuichi machida
Guru 12665 points
Part Number: MAX3232

Hello,

I would like you to confirm about below.
* According to datahseet of MAX3232 of 9.2 Standard Application, you implement 0.1uF capacitor as bypass capacitor.

However, there is no another sentence which is described value of this capacitor value aside from this section.
So, could you please confirm whether there is recommended range of this capacitor ?
Especially, we would like to know whether we can use larger value(ex 1uF, 4.7uF) than this 0.1uF.

BR,

  • +1
    TI__Mastermind 47748 points

    Hi Ryuuichi,

    The decoupling/bypass capacitor on 9.2 Standard Application of the datasheet is just a typical application template. There are capacitor values listed for C1, C2, C3, C4, because these capacitors adjust the internal charge pump circuitry. The bypass cap is for smoothing out the input supply VCC so that you short any noise to GND before powering the device. Bypass becomes especially important if there are many devices using the same power supply, or if there are specific noise frequencies you are trying to filter out. It shouldn't hurt to increase the value of the cap to 1uF, 4.7uF, etc. or have different valued caps in parallel. Too large of a bypass capacitor could cause the VCC to ramp up slowly from ground, but I think for this application it should be okay since you are in the uF region. 

    Regards,

    Tyler

  • 0 in reply to Tyler Townsend
    Guru 12665 points

    Hello Tyler-san,

    Thank you for your explanation.
    I understood I can use this bypass capacitor from viewpoint of general noise rejection.
    Since I thought there may be any specific feature for this Vcc, I asked this just in case.
    Since, I understood purpose, so I will close this thread.

    BR,