Glass Passivated Diode

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Hi, i am designing a power supply with the LinkSwitch-TN family, my question is about the feedback diode used in the design, it says it has to be a Glass Passivated diode like the 1N4007GP, but i couldnt find information about the difference with the 1N4007, the only one i found is about the specified trr, i know the 1N4007 doesnt have a specified trr, but if u dont need a fast trr, why does it have to be specific?? thank you greetings from argentina Adrian
Hi Adrian, We don't need a fast diode but we want the reverse recovery time to be within a certain range. By using glass passivated diode, we can guarantee a specified reverse recovery time. The reverse recovery time of ordinary 1N400x diode can vary a lot. Regards, PI-Scotty
thank you for your answer you said "we want the reverse recovery time to be within a certain range", which is that range?, for example, can i use a 1N4937 who has a trr of 200ns?
You should also consider whether the forward voltage drops of your feedback diode and frre-wheeling diode can match. You've already found that 1N4937 has 200ns of trr. If its forward voltage drop matches that of your free-wheeling diode, you can use it. Regards.
if u will use 1n4007, u can observe increased current at drain start up or so. also, if u use UF4007series, it will have incresed performance. Better is, if u really want a good and reliable product, use 1N4007GP. LNK-TN series is also a bit sensitive device, i found few field failures if suggested components are not used.But,if used GP....i found better results in field.

Hi, AN39 recommends a 1N4005 because of slow reverse recovery (Trr 30us typical). Modern Surface Mount equivalents for this type of rectifier give around 1us for Trr - would this be OK? What is the range of Trr that is acceptable for the design shown in AN39 and EP85? Thanks, Tim.

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