LT8316 15V/3A Output

Dear Sir/Madam

We are using the LT8316 as a buck converter for 400V to 15V. The Componets ar selected to run up to 3A.
As a test voltage we used 100V. The buck converter works well with low current. But when we increase the current, the circuit fails and the LT8316 gets destroyed.
We measure a short circuit from BIAS to GND.
Do you have any idea, why we can't get more then 500mA, before the LT8316 gets destroyed?

My schematics and layout are shown below.

Regards,
Fabian

  • 0
    •  Analog Employees 
    on May 12, 2021 4:22 AM

    Hi Fabian,

    Let me investigate it for a bit but I've been looking over your diodes, and it seems that your D1/D3 barely handles the 100V reverse voltage. Remember that your switch node is Vin at ton and so that's the stress your D3 at ton. Try to further de-rate your diode (around 80%) and see if problem persists. 

    Can you also provide scope shots for your switch node and inductor current? Thank you!

    Regards,