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LM5109: Differences between LM5109 family

Part Number: LM5109

Can you please explain the differences between LM5109, LM5109A, and LM5109B? I can see a few differences in the datasheets (no suffix has higher voltage and seems to be a bit more powerful/robust driver, A and B have slightly lower operating current and slightly higher LO side UVLO), but it's unclear to me if there are real performance differences or if any changes are more collateral (die improvement/correction, different process, moving to a new/different fab, etc.). While A and B do appear to be a different die than the original with no suffix, A and B appear virtually indistinguishable. It appears the B suffix is preferred, but I don't see anything to indicate any expected changes to a design if moving from an older version to the B version.

Also, was LM5109 (no suffix) ever released in WSON package? It's in the datasheet but not on the product page. A and B suffix versions list 2 packages.

  • Hello Evan,

    Thank you for the interest in the LM5109, A and B versions. I am an applications engineer with TI and will work to answer your questions. I am reviewing the datasheets now and will respond shortly.

    Since there are different versions, can you comment on desired characteristics for your design such as package preference etc.

    Regards,

    Richard Herring

  • Hello Evan,
    I received information about the LM5109, LM5109A, and LM5109B.
    The difference in the most recent device, the LM5109B is not related to the datasheet parameters. There are improvements implemented to the power up initialization compared to the previous devices.
    I would recommend using the LM5109B since the parameters are the same, and there have been functional improvements to the device.
    Please confirm if this addresses your concerns and questions on the conversation thread.

    Regards,
    Richard Herring
  • Hi Richard,

    Thanks for the feedback. No going from no suffix to A there were design changes to the part that changed the gate driver performance. Going from A to B, there were improvements during power up but nothing on the gate driver section.

    There are still two things I'd like to know:
    1. Are there conditions where the LM5109A could latch up or misbehave, which the B version corrects?
    2. I asked in my original post if LM5109 (no suffix) was released in WSON package or only SOIC. Can you let me know about that?

    Thank you!
  • Hi again Richard (or anyone else who can answer),

    No response on the questions above? Can you please help to tie up these loose ends?

  • Hello Evan,

    For the 1st question you asked there is an improvement to the LM5109B from the LM5109A. The change to the LM5109B guarantees that in the case of the VDD falling below the operating point the high side driver is guaranteed to be forced to a low state. So there may be a case where falling VDD, and VHB still high, the LM5109A could have the high side output left in the high state.

    Since the LM5109A and B have the same parameters, and there is a functional improvement to transient conditions of VDD, we would recommend the LM5109B. 

    For the LM5109 (original part) the datasheet orderable numbers are listing the SOIC package only, and not the WSON. The LM5109A has both the SOIC and the WSON packages available; and the LM5109B has both SOIC and WSON packages available.

    Regards,

    Richard Herring