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Drive GaN Switch

1886332
Expert 1325 points
Other Parts Discussed in Thread: OPA453, LM5113

Hi,

I'm looking to drive GaN SW that has controls . On each control I need to have 0V or -40V (prefer -60V).

I need op amp that will act like comparator when I put "0" the comparator/opamp output will be 0V

When the input is +3.3V the comparator/opamp output will be -40V .

I need to drive ~5mA at the peak and continues ~1mA.

 

Does the OPA453 can fit this requesets?

Thanks,

Ziv

  • 0
    Guru 21975 points

    Ziv,

    While the OPA453 could be configured to perform this function, it would appear to not be an ideal fit for the application. Since linear control of the output voltage is not required, a transistor switch circuit would probably be more efficient. Furthermore, the op amp slew rate would limit the switching speed. It would require up to 10us for the OPA453 to slew 60V. GaN switches are generally used for very fast switching of RF signals.

    Perhaps we misunderstand the application and you can explain why you believe an op amp circuit would be effective.

    Regards, Bruce.

  • 0 in reply to Bruce Trump
    Expert 1325 points

    Hi Bruce,

    Can you recommend for fast op amp or can you assist with designing such circuit?

    Thanks,

    Ziv

  • 0 in reply to 1886332
    Guru 21975 points

    Ziv,

    I am not aware of a high voltage op amp that is much faster than the OPA453. The internal phase compensation of an op amp makes it much slower than transistor switching circuits. I think a transistor switching circuit would be the best solution.

    Regards, Bruce

  • 0 in reply to Bruce Trump
    Expert 1325 points

    Hi Bruce,

    Is it possible to use the LM5113?

    Thanks,

    ziv

  • 0 in reply to 1886332
    Guru 21975 points

    Ziv,

    The LM5113 appears to be suited to driving a positive voltage drive for GaN switches. In general, however, this devices looks much closer to the type of driver that you need. The LM5113 is not generally supported on this forum. I will find a responsible person who can better comment on this type of product.

    Regards, Bruce.

  • 0 in reply to Bruce Trump
    TI__Prodigy 310 points

    Ziv,

    LM5113 is designed for enhancement mode GaN FETs. It seems that you are using depletion mode GaN FETs. If that is the case, LM5113 will not be a fit. If you have more questions related to LM5113, please post your questions on power management forum. 

    Regards,

    Min Chen

  • 0 in reply to Min Chen
    Expert 1325 points

    Hi,

    Can you help with designing such a circuit?

    Thanks,

    Ziv