Buck or LDO

Hello team,

I am rather confuse on my selection of using LDO or using buck.

My power input range from10.8V-13V and I require a regulated  output of 10V and 1.2A.

I am currently looking at LTM8074 and LT1965.

Which would be more suitable for my use? I am aware that buck would provide a better efficiency but am concern if the switching frequency what is the effect of the switching freq/ what to set, based on table 1 of LTM8074 datasheet. Or am I selecting a wrong buck regulator to start with.

Thanks in advance

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    •  Analog Employees 
    on Jul 29, 2020 1:49 AM

    Hi Ink,

    Apology for late reply. I did a quick search and I find at least 36 buck parts that should worth looking. LTM product is good candidate if you're looking for the minimum number of components.
    www.analog.com/.../11491

    Between a buck and an LDO, efficiency will be one big factor for you. At worst VIN 13V, you can have 3.6W of power dissipation in LDO.  I don't think this is good way to go.

  • Hi Fil,

    I have another question does buck regulators have a voltage dropout requirement? in order for it to regulate the voltage effectively? Eg: Is the switching regulator am to give me a +5V regulated voltage from Vin of +5.25V to 6V? I have been using LDO due to the dropout voltage. Is LTM4624 suitable? I have input it in to the LTpowerCAD but the TonffVin max is in red what is the issue with this selection? 

    Hop you can advise me on this .. 

    Thanks inadvance

Reply
  • Hi Fil,

    I have another question does buck regulators have a voltage dropout requirement? in order for it to regulate the voltage effectively? Eg: Is the switching regulator am to give me a +5V regulated voltage from Vin of +5.25V to 6V? I have been using LDO due to the dropout voltage. Is LTM4624 suitable? I have input it in to the LTpowerCAD but the TonffVin max is in red what is the issue with this selection? 

    Hop you can advise me on this .. 

    Thanks inadvance

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