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TIDA-01168: Questions about GaN MOSFETs

Part Number: TIDA-01168
Other Parts Discussed in Thread: LMG3410R070, LMG3410R150, LMG3410R050

Hello,

My group is trying to examine the simulations of the TIDA-01168 reference design to eventually study integrating wide band gap MOSFETs in products to examine the difference in efficiencies.

We would like to change out the given MOSFETs and any others in the schematic for the power stage in figure 18 of the reference design datasheet.  We want to examine if replacing the suggested MOSFETs in the power stage would change how efficient the circuit would work.  

However, our group is a group of students that do not have much knowledge on what to look for when researching GaN MOSFETs and how one would integrate them into a circuit.

Are there any GaN MOSFET recommendations that anyone can suggest to replace the given MOSFETs in the schematic?  Any explanation on how to pick and choose a GaN MOSFET would be greatly appreciated so we can learn!

Thank you,

Joseph Wong

  • Hello Joseph,

    Thanks for reaching out!

    Some key parameters you can look for while choosing the GaNFET are the following:

    Rdson - It decides how much resistance the GaNFET will have while conducting;

    Max Vds - Maximum drain to source voltage the GaNFET can handle;

    Coss - Output capacitance relates to the loss during switching;

    Dv/dt - How fast the FET can turn on; relates to the switching loss;

    Vsd - Voltage drop while the FET is operating at third quadrant mode.

    Ids - Maximum drain to source current the device can handle.

     Often times, the bigger the Rdson, the smaller the Coss because the size of the die. You need to choose these parameters based on the switching frequency of the circuit as well as the conduction current.

    One key benefit of the GaNFET is the lack of the reverse recovery loss due lack of the body diode. While the circuit is operating at high switching frequency, the reverse recovery loss of the MOSFET body diode will become dominant.

    Another benefit of the GaNFET is due to the reduced switching loss, the switching frequency could be pushed higher, which makes the passive component size to be reduced.

    However, a lot of the benefit of the GaN comes with the good layout of the circuit board, meaning the common source, power loop, gate loop inductance needs to be minimized to get a great slew rate as well as the minimized overshoot.

    With TI's LMG3410 family of device, the gate driver is integrated into the package with the GaNFET, which ensures that the gate loop and common source inductance is minimized. LMG3410 family currently has three devices: LMG3410R050, LMG3410R070 and LMG3410R150 devices with different parameters mentioned above. While selecting the device, make sure the maximum voltage and current ratings meet your application requirement.

    Please let me know if you need any other information or have other questions.

    Regards,