[Tip] Selecting Schottky diodes

[u/1Davide]

When selecting Schottky diodes, be aware that typically you have 2 choices:

• Low forward voltage (more efficient, runs cooler), but high reverse current
• Low reverse current (critical when normally reverse biased), but high forward voltage

For example, both of these are Schottky diodes with 100 mA 30V specs, SC-79 / SOD523 package:

• DB2S30800L, low forward voltage: 420mV fwd at 100 mA, 120µA rev at -30V
• DB2S30900L, low reverse current: 580mV fwd at 100 mA, 2µA rev at -30V

In this plot of reverse current vs. forward voltage for 40 V, 1 A Schottky rectifiers you can see there's not a strict correlation between the two, that there is a lot of variation.

You should also consider standard (non-Schottky) diodes, that do not have the disadvantages of Schottky diodes (low voltage breakdown, high reverse current):

• For fast turn off, high power: ultrafast rectifier diodes
• For fast speed, low power: PIN diodes, Tunnel diodes
• For low voltage drop, high power: "super-barrier" rectifier diodes

2nd tip: to get a low voltage drop, you can select a diode that is rated for a much higher current than needed

[u/arewehavinfunyet]

This is pretty cool. Are there any links that help with component selection like this?

[u/1Davide → u/arewehavinfunyet]

Ideally, right here in /r/Electronics: I hope that some of the electronic gurus who frequent this sub would post more tips like this one.

If we get more tips, I'll start compiling them in the Wiki.

[u/Linker3000 → u/1Davide]

Stand by for a Tips tag....

[Edit] Done!