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LM5149-Q1: LM5149-Q1

Part Number: LM5149-Q1
Other Parts Discussed in Thread: LM25149-Q1, LM5148-Q1,

Hi, as you know before prototyping, having properly worked simulation is always better. Spice model of LM5149-Q1 is not avaliable now. Also ıt is not included in PSpıce For TI. Could you provide me spice model please?


  • Hi, Because of the space restriction application, I want to apply  Design 4 – Dual-Phase 400-kHz 20-A Synchronous Buck Regulator in the LM5149-Q1 datasheet. The schematic is given 52th page. If I use Passive EMI Filter instead of Active EMI Filter, Should I connect 5 pin(INJ, SEN, AEFVDDA, AVSS, REFAGND) of both primary and secondary IC to ground.

    And what happens EN pin of the IC in this Dual Phase configuration. Should I connect them together to VIN pin?

    And for the single IC operation it can be Design 3 – High Efficiency 440-kHz Synchronous Buck Regulator that given in the 48th page of the datasheet. REFAGND pin is connected to AEF sense point. What is the meaning of the AEF sense point. Where is the best point to connect them together ? And the point that is going to be connected is same for the Dual Phase operation ?


  • Hi Riza,

    The LM5149-Q1 PSPICE model will be released soon.

    You can use LM25149-Q1 PSPICE model in the meantime. However dual-phase is not supported in the PSPICE model.

    If you use passive EMI filter you can leave the AEF nodes floating. Most nodes can be GNDed just not AEFVDDA.

    Also you can consider LM5148-Q1 without AEF which will be releasing soon.

    Regarding AEF GND, check out  the LM5149-Q1EVM-400 layout, (images in EVM user guide).

    Essentially, the GND should be close to the input GND, and away from PGND and any noisy GND node.

    The EN pins can be tied together, or you can use a duplicate EN resistor divider on the second phase.

    Hope this helps,


  • Thank you. It helps a lot.