LT3743EUFD - SW Pin is burning out

Hi Singlejd123 ,

Thank you very much for reaching out and for your participation in this community.
I have contacted the ADI experts on this device to help respond to this query.
We hope to give you an update as soon as possible.
You may also try reaching out to local FAE to provide support on the product.

Regards,

Noel

Hi Jason,

It is not common that bootstrap circuit causes damage of SW. Abs. maximum of SW pin is 40V, while Vin is 36V. During switching there might be SW pin voltage overshoot and exceeds the abs. maximum. Other possibility is input supply has transients >40V. You may probe and check these voltages. 

Hi Gengyao,

Thanks for your reply and help. Yes, I can confirm that there is an overshoot on the SW pin which approaches the absolute maximum of 40V. For now, I'll have to use the driver PCB at lower voltage stages of the laser (seed and preamplifier) and redesign the high power stage. 40V is too close to our supply voltage, so I'll use the LT3763 instead which does have a higher 60V rating.

Best regards,

Jason