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LMG1020: Faster alternative to LMG1020 for SOA amplitude modulation

Jacob Campbell
Prodigy 35 points
Part Number: LMG1020

Tool/software:

My situation is this: I am designing a circuit to drive a semiconductor optical amplifier (SOA) on and off at 50% duty cycle as fast as possible. High extinction ratio is required. I would ideally like to switch around 200-300Mhz, but the LMG1020 datasheet says it can only go up to 60 MHz. The current while the amplifier is on is around 300mA but a design to support 1A would be best (from a supply of between 3 and 5V). I know that the in the gate driver + FET approach the current is limited more by the FET thermals than the gate driver, I am just giving context. 

Are there any other gate drivers capable of better performance than this? Please advise if there are or if a different approach would be better to drive the SOA.

  • 0
    TI__Genius 9770 points

    Hello,

    The main limiting factor to the LMG1020 max switching frequency is the load or FET gate capacitance. This will affect the rise and fall time. The next limiting factor would be the gate loop layout and component placement. The LMG1020 can theoretically achieve higher operating frequency, but we do not guarantee that it will perform within the characteristics defined in the datasheet if exceeding 60MHz.

    Thank you,

    Walter

  • 0 in reply to Walter Zollinger
    Prodigy 35 points

    So the LMG1020 can exceed 60Mhz with good layout. Assuming the layout is as good as possible are there faster gate drivers available at TI? 

  • 0 in reply to Jacob Campbell
    TI__Genius 9770 points

    Hello,

    It could be possible with the driver's timing specs but as said before we do not guarantee that it will perform within all the the characteristics defined in the datasheet if exceeding 60MHz. The GaNFET being driven will also have a significant effect on the maximum switching speed.

    LMG1020 is our fastest gate driver.

    Thanks,

    Walter