LTC4364
Recommended for New Designs
The LTC4364 surge stopper with ideal diode controller protects loads from high voltage transients. It limits and regulates the output during an overvoltage...
Datasheet
LTC4364 on Analog.com
Hi Sir,
The LTC4364 design input range is +12V to 48V.
We had add Bi-directional TVS SMCJ58CA at input side. When we do the surge test at negative 500V, we can found -47V at the input and this negative voltage will cause LTC4364 trigger reverse current protection right? How can i avoid this issue when we do the negative surge test. We can solve this issue if we use Uni-directional SMCJ54A at input side. But this will cause SMCJ58A damage when our input connector plug in reverse. How can we to avoid this negative voltage surge issue when we need to use Bi-directional TVS?
Hi
Yes, it will trigger the reverse input protection to protect the downstream load. It is actually a good thing. However, some of the pins are rated to -40V. I would recommend using two TVS diodes with different breakdown voltages connected cathode to cathode. See diagram below. You can still use SMCJ58A (NOT CA) for protecting positive voltage spike and SMCJ20A (NOT CA) for clamping negative spike. With SMCJ20A it will clamp around 22V to give plenty of margin for -40V rated pins.
I also noticed that you are using ceramic capacitors at the output. I would recommend using 22uF minimum Electrolytic capacitor with ESR of 4mΩ to 100mΩ. This capacitor is needed to stabilize the control loop during input voltage surge event. If you still plan to use ceramic capacitor I would recommend putting some ESR resistor (4mohm to 100mohm) 1210 or 2512 size in series with the ceramic cap. See diagram below.
