On-resistance of a schottky diode

[dko]

How can I find the on-resistance of this schottky diode? I can't find a direct value in the list. I think I should read it in the graphs but I don't know how.

https://www.digchip.com/datasheets/parts/datasheet/232/19TQ015-pdf.php

Thanks beforehand!

 

[IanP]

As far as Schottky Diode is concerned one can not talk about R(on) but rather about it’s dynamic resistance defined as follows:

Rd = ΔVf/ΔIf

This can be easily obtained from the [Vf versus If] chart (see attached plot) and make sure that that ΔVf=Vf2-Vf1 is reasonably “small" ..

Rgds,
IanP

 

[FvM]

The question isn't particularly clear. The above diagram illustrates however, that the dynamic diode resistance has two components, an ideal diode term ut/id and a constant bulk resistance. The ideal diode characteristic would appear as a straight line in the half-logarithmic diagram. It can be seen at low currents.

 

[dko]

Thanks a lot to both of you!

I also have another question. I would need the Thermal Resistance, junction to ambient. But in the list I can only find values for junction to case and case to sink. Can I somehow use these to get the Thermal Resistance, junction to ambient?

 

[IanP]

If I understand your question correctly you are after the thermal resistance of a device in the case style TO-220 without external heatsink ..

Here it is:
Case Style => TO-220 => Thermal Resistance (no heatsink) => 75-80°C/W

On top of that you should add 1.5°C/W (junction-to-case) but comparing with the value of, say, 80°C/W it can be just neglected ..

Rgds,
IanP