How to find out reverse recovery time in a Diode

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mohan.n2293

Joined Jan 23, 2017
60
Hi all,

I need to know how to calculate the trr(reverse recovery time )for a diode,in some data sheet they are specifying but in the below datasheet im not getting how to see the trr value somebody please help me.
 

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ian field

Joined Oct 27, 2012
6,536
Hi all,

I need to know how to calculate the trr(reverse recovery time )for a diode,in some data sheet they are specifying but in the below datasheet im not getting how to see the trr value somebody please help me.
They frequently don't bother listing Trr on Shottky barrier rectifiers - I don't know why.

SB rectifiers are faster than any plain silicon types.

Silicon carbide are claimed to be faster still - but they have horrendous Vf.

In a SMPSU application; large reverse recovery spikes will reveal themselves by heating the reservoir electrolytic down wind.

SB rectifiers also tend to have higher junction capacitance, the best remedy is to swamp it out by padding the electrolytic with smaller capacitors, ceramic is a good choice but hard to find big enough.

Sometimes you have to make the best out of bad Trr - this can be anything from a ferrite bead on the rectifier lead, to a choke with about 4 - 6 turns of fat wire on a ferrite slug.
 

crutschow

Joined Mar 14, 2008
34,201
From Wikipedia:
The most important difference between the p-n diode and the Schottky diode is the reverse recovery time (trr), when the diode switches from the conducting to the non-conducting state. In a p–n diode, the reverse recovery time can be in the order of several microseconds to less than 100 ns for fast diodes. Schottky diodes do not have a recovery time, as there is nothing to recover from (i.e., there is no charge carrier depletion region at the junction).

Obviously then, since they do not have a reverse recovery time, there is nothing to list in their data sheets.
 

ian field

Joined Oct 27, 2012
6,536
From Wikipedia:
The most important difference between the p-n diode and the Schottky diode is the reverse recovery time (trr), when the diode switches from the conducting to the non-conducting state. In a p–n diode, the reverse recovery time can be in the order of several microseconds to less than 100 ns for fast diodes. Schottky diodes do not have a recovery time, as there is nothing to recover from (i.e., there is no charge carrier depletion region at the junction).

Obviously then, since they do not have a reverse recovery time, there is nothing to list in their data sheets.
Sure I've seen Trr quoted - but very rarely.
 

crutschow

Joined Mar 14, 2008
34,201
Sure I've seen Trr quoted - but very rarely.
Well Schottkys do obviously take a finite time to turn off, but it's not a reverse recovery phenomenon so technically it shouldn't be called Trr.
It should just be called reverse turn-off time.
 
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