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LMZM33606: LMZM33606 COUT capacitor slection help

Mome_MGE
Intellectual 270 points
Part Number: LMZM33606

Hello,

I have been having problems with the selection of capacitors, due to shortages in supplies, at the moment we have 1206 pads.

But my question is what range of capacitors could we select.

At the moment the setting for the LMZM33606 is:

Input Voltage: 15V to 24V

Output Voltage: 12V

Current Output 4A used continuously

Switching Frequency approx: 865.337 KHz

At the moment we used 22uF at 35V 20% 1206

What is the range we could use for different values?

Mo

 

 

  • 0
    TI__Guru 50120 points
    Hi Mo,

    Following Table 3 datasheet recommendation, for Vout=12V application, the output capacitance should be at minimum 50uF and be rated for at least 25V which is twice the output voltage rating. Please take capacitor DC bias effects into consideration during design. The higher the output capacitance the less voltage deviation there will be during a load step condition.

    Regards,
    Jimmy
  • 0 in reply to Jimmy Hua
    Intellectual 270 points

    Hello,

    At the moment I have found 22µF ±20% 25V Ceramic Capacitor X5R 1206, which I have 10 placed in parallel to ground.

    Would you think that would be enough?

  • 0 in reply to Mome_MGE
    TI__Guru 50120 points

    Hi Mo,

    The amount of capacitors on your output should be fine for proper operation of the power module. By any chance are you using the GRM31CR61E226ME15 capacitors as these will be discontinued in the future based on Murata's website.

    Because of this you might want to use the GRM32ER71E226ME15 which is a 1210 case size for 25V rated and X7R. Using this will also allow you to use fewer Cout components( 6 instead of 10). 

    Regards,

    Jimmy 

  • 0 in reply to Jimmy Hua
    Intellectual 270 points

    No That was the original part I chose a while back now we are going with TDK C3216X5R1E226M160AB.

    Mohammed Al-Amin

  • 0 in reply to Mome_MGE
    TI__Guru 50120 points

    Hi Mo,

    I believe that should be fine. The effective capacitance at the DC bias of 12V output will be as follows:

    Since you have ten of these in parallel, your output capacitance will be over 50uF. This should work.

    Regards,

    Jimmy