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LMG1210: Oscillation problem using LMG1210 and EPC2021

Part Number: LMG1210

Hi Team,

My customer using LMG1210 to drive EPC2021 GAN mosfets for amplifier application

 

Here is a description of the problem

 

When I work with the amplifier at a low voltage of 12V there is no problem. The amplifier works well.

 

When I increase the Voltage of the mosfets while the amplifier is working up to 40V there is no problem.

 

But when I set Voltage to 40V and then set the enable line of the LMG1210 to high and start toggling the PWM line the Upper mosfet is damaged immediately.

 

There is an oscillation at 128Mhz as shown in the diagram below. 

   

I need help to understand how to solve this problem

 

(There is no load on the amplifier output)


The EPC2021 got damaged because of an oscillation that occurred when the toggling started. see next diagram that explain it.

Thanks,

Shlomi

LMG1210.docx

  • Hi Shlomi,

    Thanks for posting on E2E. Please help clarify:

    1) For Vo, do you mean the voltage between GaN half bridge mid-point to the ground? and it has 20V peak-to-peak noise on top of 40V?

    2) What's the PWM frequency and what's the deadtime settings for DHL and DLH? It is hardly to see for the diagram.

    Regards,

    Gangyao