Substitute diode for step-down SMPS

[vvanders]

I've got a project that's using a **broken link removed** to step 9V down to 3.3V, the datasheets recommend a 1N5817 diode however I can only find it in a through hole package and I'm pretty tight on board space(need to fit in 1" x 3").

What should I be looking for in a surface mount schotty diode to replace it? The datasheet isn't a ton of help and I'm not terribly familiar with SMPS enough to pick one out.

 

[crutschow]

Any 1A, 20V Schottky diode should work.

Or you could mount the diode vertically in cordwood fashion, which takes up much less board room, as long as the vertical height isn't a problem (.205" for the diode body length plus some lead wrap around distance).

 

[vvanders]

Actually, mounting the diode like that is brilliant.

The board will be subjected to at least 20 G's but with the light weight of the diodes it should be fine.

 

[crutschow]

Actually, mounting the diode like that is brilliant.

The board will be subjected to at least 20 G's but with the light weight of the diodes it should be fine.

That design goes back many years and is used on many small circuit boards. In my early days my company built a compact circuit module with four preamps by placing all the components vertically between two small circuit boards like a sandwich (The system it was in had 350 preamps). You can stuff a lot of through-hole components on a board if they are all vertical. But replacing a component was impossible after the board was built.