NEED HELP FOR LTM4620A (5V/25A)

Hi, 

 We are using above circuit for 5V/25A.

Above circuit is it working ? or any changes require?

can you give me feedback

  • Hi,

        One more question related LTM4620

    If I am remove the input Electrolytic capacitor ( 56uF/20V ) in above circuit,is there any changes happen output side?.

    I need require output voltage is 5V/25A ( Vpeak-peak Ripple < 10mV).

  • 0
    •  Analog Employees 
    on Jan 11, 2018 10:26 PM

    Hello

    Can we have a higher resolution picture to review the schematic?

    DC1759A is the demo board designed for two output but can also reconfigured to single output when

    RUN, TRACK, VFB and COMP pins between two phases are tied together.

    This could be reference for  your design.

    http://cds.linear.com/docs/en/demo-board-schematic/1759asch.pdf

    Input capacitor is used to provide a stable input voltage. Ripples in the input voltage will also affect the output voltage ripple. What is the other capacitor values in the input?

    Is the 10mV peak to peak ripple at steady state ? Or during dynamics?

    10mV  equals to 0.2% of 5V. This will require carefully selection of output capacitor type and numbers (much bigger).

    Is this requirements stringent?  1% output voltage ripple at full loading is normal practice.

    Thank you.

  • We are using above circuit for 5V/25A

    Input voltage is 12V

    I need require output voltage is 5V/25A ( Vpeak-peak Ripple < 15mV)

    Is that enough The input and output decoupling capacitor to getting the output voltage is 5V/25A ( Vpeak-peak Ripple < 15mV)

    Above circuit is working as what we expect? or any changes require?

    Please review it and can you give me feedback for whole circuit.

    Thanks and regards 

    R.Rengasamy

  • 0
    •  Analog Employees 
    on Jan 12, 2018 2:49 PM

    Hello R.Rengasamy,

    to check if the intended output caps are sufficient for your ripple requirements please check the LT4620A circuit in our LTPowerCAD tool (Download from our webpage). Additionally you can simulate your circuit with LTSpice. But as mentioned above 15mV are pretty tough resp. demand for decent amount of output caps.

    What you should consider as well is the maximum Pout of 125W in total. Even with the high efficiency of the LTM4620A the thermals are challenging. From the Power loss curve in the datasheet on page 28 you will get nearly 7W of losses, which will lead to a considerable amount of heating (30-50C above ambient), depending on your layout (copper thickness, pcb space). What is the specified ambient temperature for your application?

    I won't review your circuit, the LTMs are pretty easy to use parts, hence if you follow the guidelines from the ds (example for your config does exist there as well) and my remarks above  the likelihood of a proper function is extremely high.

    Have fun!

    Markus

  • 0
    •  Analog Employees 
    on Aug 2, 2018 4:00 PM
    This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

    Thank you,
    EZ Admin