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.


  • 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!