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MC33063A: BUCK configuration

James Zhan
Expert 4365 points
Part Number: MC33063A

Hi team,

According to the datasheet in 9.2.3, buck configuration would need an diode as below picture in red circle.

My customer is using MC33063A buck for 12V to 5V without the diode(D1) in second picture, but it still output 5V.

Could we remove this diode? Would it have any risk?

Could you please help to provide some insights for this?

Thanks.

  • 0
    TI__Mastermind 21565 points

    Hi James:

    This diode is necessary for Buck converter. Otherwise it's hard for inductance freewheel, and will bring voltage spike and has the risk to damage the FET.

    Our expert for MC33063 is out of office about one week. He may have more comments. Please wait with patience. 

  • 0 in reply to Minqiu Xie
    TI__Mastermind 21565 points

    Hi James:

    Sorry for keep you waiting, the expert for MC33063 is still out of office these days.

    From my views, generally, there is a diode inside IC from the ground to the Pins. It will help freewheel in some case, but it has limited capability. So it's recommend to add a diode outside.