Maximum current of Schottky diode

[Henry Tong]

Dear all,

I am a layman to Schottky diode and would be grateful if anyone could answer my question. Thank you.

Is there anyone who knows why the maximum forward current of this schottky diode is 6.9A as opposed to 2A?

**broken link removed**

Best Regards,
Henry

P.S. I am new to this forum. Please remind me if I violate any rules of this forum.

 

[Henry Tong]

Schottky diodes comparison problem

Dear All,

I have been comparing the spec. of the following 2 datasheets:

**broken link removed**

https://www.genesicsemi.com/images/products_sic/rectifiers/GB02SLT12-252.pdf

For the former one, I discovered that the max. forward current is exceptionally larger than is expected 6.9A. It is suppose to be a 2A 1200V Schottky diode. Could anyone please tell me the reason for 6.9A and help me compare the two diodes. Thank you.

Best Regards,
Henry

P.S. Please correct me if I posted in the wrong area.

 

[tendi]

According to the datasheet, this diode is designed for a forward current of 6.9amps continuous current. A pulsed current rating is even higher than this(up to 14amps)! So your question as to why this diode takes 6.9A as opposed to 2A is answered simply because that is the design current of the device. If you want less current handling devices then you can check with semiconductor data-books and make your selection.

 

[Henry Tong]

According to the datasheet, this diode is designed for a forward current of 6.9amps continuous current. A pulsed current rating is even higher than this(up to 14amps)! So your question as to why this diode takes 6.9A as opposed to 2A is answered simply because that is the design current of the device. If you want less current handling devices then you can check with semiconductor data-books and make your selection.

Thanks for your info.

Added to the question, if 6.9A is the designed forward current that the diode can withstand, how come the forward voltage(at max 3V with 2A & 175dC) is not tested with 6.9A instead of 2A?

Regards,
Henry

 

[tendi]

I see that you're now comparing two datasheets of diodes from different manufacturers, GB02SL...& C4D021...? And all can withstand 1200v Vrrm. But the maximum forward current, I-f for the GB021.. is 2A while for the C4D021.. is given as 6.9A, right? The different makers here are claiming different ratings for their devices and that is not your problem, right? You have a problem where the makers are quoting the voltage drops across the diodes, right? These Vf ratings are given as 1.75v max at a sampling current of 2A when measured at 25 deg for the GB021.. diode whilst the Vf for the C4D021 is given as 1.8v also at a sampling current of 2A. May I add that these are the maximum voltages that are lost across the diodes as they carry load current. It is just a standard here that they are compared as they carry only 2A, which happens to be the maximum forward current of the GBO21 diode. Is this clear?

 

[Henry Tong]

I see that you're now comparing two datasheets of diodes from different manufacturers, GB02SL...& C4D021...? And all can withstand 1200v Vrrm. But the maximum forward current, I-f for the GB021.. is 2A while for the C4D021.. is given as 6.9A, right? The different makers here are claiming different ratings for their devices and that is not your problem, right? You have a problem where the makers are quoting the voltage drops across the diodes, right? These Vf ratings are given as 1.75v max at a sampling current of 2A when measured at 25 deg for the GB021.. diode whilst the Vf for the C4D021 is given as 1.8v also at a sampling current of 2A. May I add that these are the maximum voltages that are lost across the diodes as they carry load current. It is just a standard here that they are compared as they carry only 2A, which happens to be the maximum forward current of the GBO21 diode. Is this clear?

Thanks tendi, I have a better understanding now.

The datasheet of C4D021 just manifests it can tolerate a larger current without being damaged.

 

[FvM]

I think the previous answers can't be verified in the datasheet.

Both diodes have almost similar typical specifications, thermal resistance of said "6.9A" diode is even larger than of the "2A" diode. Reference temperatures are however different (factor 2 in difference to maximum temperature) and apparently the manufacturers are applying considerably different margins for type variations (like "worst case" thermal resistance etc.)

So the different specification are mainly showing different degrees of conservatism regarding applicable operation conditions, or implicitely, different lifetime expectations.

An additional point not addressed in the datasheets. These are SMD parts. You may want to ask about realistic junction to ambient thermal resistances achievable with surface mounted heat sinks or other cooling methods applicable in SMD design. You'll surely end up in a considerably lower maxim power dissipation than assumed in the datasheets.

 

[Henry Tong]

I think the previous answers can't be verified in the datasheet.

Both diodes have almost similar typical specifications, thermal resistance of said "6.9A" diode is even larger than of the "2A" diode. Reference temperatures are however different (factor 2 in difference to maximum temperature) and apparently the manufacturers are applying considerably different margins for type variations (like "worst case" thermal resistance etc.)

So the different specification are mainly showing different degrees of conservatism regarding applicable operation conditions, or implicitely, different lifetime expectations.

An additional point not addressed in the datasheets. These are SMD parts. You may want to ask about realistic junction to ambient thermal resistances achievable with surface mounted heat sinks or other cooling methods applicable in SMD design. You'll surely end up in a considerably lower maxim power dissipation than assumed in the datasheets.

Thanks. But in reality, it is hard to compare their lifetime as operating condition is varied, and having just a higher thermal resistance does not imply it can enjoy longer lifespan when run at a optimal temperature, right?