This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LM5143: LM5143 MOSFET design

Part Number: LM5143

Hi,

We use the LM5143 for the buck design, and the input voltages is 48VDC, and output voltage is 20-40VDC, output current is 30A max, 

Now the MOSFETs will breakdown, and please kindly review below schematic diagram and advise if there are any error, thanks.

4路48V大电流驱动板V1.1_3(1).pdf

  • Hi Zhang,

    Please send a completed quickstart file for this design.

    Regards,

    Tim

  • Some comments on the schematic:

    1. FETs are small 3 x 3mm package and relatively high Rdson - not suitable for high current. Paralleling these FET increases inductive parasitics. Much better to use 5 x 6mm FETs for lower temperature rise and lower parasitics.
    2. 100 Ohm + 1nF is a 100ns time constant - this is a lot of filtering on the current sense.
    3. VCC caps should be 2 x 2.2uF, not 2 x 470nF.
    4. 220uF/63V output electrolytics have very high ESL and ESR - not good for high-frequency filtering. Replace with ceramics. What is the required Vout range? Choose ceramic caps with voltage just above that (100V seems excessive here).
    5. SYNCOUT should be left open circuit - no need to load it with 1k.

    --

    Tim