Diode comparison(UF5408-HER208)

[qolpa]

uf5408

hi,
i have two diodes HER208 and UF5408. they have same elecrical rating except HER208 is 2A and UF5408 is 3A.
when i tested the diodes in my circuit 5408 becomes very hot (60-70 °C) while 208 is at normal temp(30-40 °C). and i know from another test with very small voltages, 5408 is drawing much current than 208 (50mA vs 5mA).

i could not find the reason. any idea?

regards

 

[explorick]

her 208

What is the input given across diode. Is it a DC voltage or a square input? Did you try with another UF5408?

 

[qolpa]

diode characteristics comparison

actually its a square wave. D3 in the figure below.
and yes i tried 2-3 more but results are same.

**broken link removed**

regards

 

[explorick]

comparison diode

One difference I observe is the reverse current between the diodes. UF5408 has a high reverse current (twice of HER208). So if the diode is in reverse bias for more time obviously the power consumption increases. But the power consumption wil be considerable only at higher voltages as the reverse current is in micro amperes.

 

[qolpa]

diode comparison

hi,

i noticed that but even if i worked with small voltages, like DC bus=25V, uf5408 draws 10 times bigger current. i found no reason for that.

regards.

 

[muhammadali_16]

i have also used both the diode. there is no comparison of UF wid HER. UF is current beneficent and also its frequency response is effective.

im working on very precise effective power supply. for that purpose i need SPICE model of UF5408. if anyone have that, kindly share that.

Best of Luck