Overshoot at SW pin on LT3590

Hi, Mike.

I tested with an evaluation board and could see an ~2 V overshoot.

2~3 V overshoot is fine in terms of the switching loss and maximum voltage rating of inside switch.

Also, part of the overshoot comes from probe ground loop.

So the actual overshoot is typically lower than what is measured with a long ground loop.

Are you concerning about EMI?

If so, you can try a RC snubber. (RC in series)

Add the RC snubber across 'SW' and 'GND'. ( R < 10 Ohm & C < 10 nF would be a good starting point)

But it will slow down the switching speed and thus, increase the switching loss.

So you may want to monitor the temperature of LT3590 while you are testing the RC snubber.

I hope it is helpful.

Best,

Yonghwan Cho

Hi, Mike.

I tested with an evaluation board and could see an ~2 V overshoot.

2~3 V overshoot is fine in terms of the switching loss and maximum voltage rating of inside switch.

Also, part of the overshoot comes from probe ground loop.

So the actual overshoot is typically lower than what is measured with a long ground loop.

Are you concerning about EMI?

If so, you can try a RC snubber. (RC in series)

Add the RC snubber across 'SW' and 'GND'. ( R < 10 Ohm & C < 10 nF would be a good starting point)

But it will slow down the switching speed and thus, increase the switching loss.

So you may want to monitor the temperature of LT3590 while you are testing the RC snubber.

I hope it is helpful.

Best,

Yonghwan Cho