[SOLVED] Laptop TVS diode compatibility

[chickmazta]

Good day guys. Please excuse me if I posted this in the wrong section, since its also related to computer I might as well start here. I have a laptop acer aspire one aod257 and a tvs diode got fried. I already knew what type diode it is. Its a Littlefuse tvs diode part number SMAJ20A.

Here's my question are SM340A and SMAJ20A different? Or they do similar functions? I've been having some problem finding the exact model. So I'm looking at unusable motherboards I have here at my house. I've been reading both datasheets and I'm a little confuse at what I am reading:?: As far as what I have understood these diodes both acts as a fuse? please correct me if I'm wrong. Hope someone helps thanks in advance.

 

[betwixt]

I can't help with specifications, you would do better to look on Littelfuses web site for that.

A TVS is device to prevent excessive voltage across it's ends by becoming conductive and passing enough current through itself to load down the source of the voltage. If it fried, it means too much voltage was applied across it and you need to sort that out first.

A replacement has to be of the same voltage rating and at least the same power rating, higher power is acceptable but not lower. If you pick one with a higher conduction voltage it will no longer provide protection to the rest of your board. If you pick one with too low a conduction voltage, it will operate in normal use and either burn out again or damge the PSU.

Brian.

 

[chickmazta]

Thanks for the explanation, I clearly understand what I should consider when replacing a component. This component SMAJ20A is a Transient Voltage Suppressor while SM340A is a Schottky Barrier Rectifier.

So now I know they are different. SMAJ20A is the burned component I was thinking of replacing it with SM340A because they look similar especially in size. Good thing I thought of it twice.:grin: