I'm working on a project which involves setting the clock on a Pi Pico over USB and then seamlessly switching over to battery power when the USB connection is removed. How to accomplish this is documented in the PDF for the Pi Pico, with the following diagram:

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Try as I might, I can't find or figure out what Schottky diode to use. I'm thinking that the battery supply voltage will be around 3 - 4.8V (3xAAA or 4xAAA NiMh cells). The maths involved in calculating which diode is just a bit beyond me.

PDF source, section 4.5.


There are tons of Schottky diodes that will do the job.

You need one that can handle the current drawn by the Pico.

An obvious choice would be to use the one already in the design.

MBR120VLSFT1G or an equivalent.

  • \$\begingroup\$ Would this work? It's as close as I could find but hole mount rather than smd: uk.rs-online.com/web/p/schottky-diodes-rectifiers/6254972 - the only difference I can see is Peak Non-Repetitive Forward Surge Current is 20A rather than 45A on the smd.. would that matter? \$\endgroup\$ – John Hunt Feb 19 at 9:45
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    \$\begingroup\$ It has a little bit higher forward voltage drop, but it wont matter. It will work just fine. \$\endgroup\$ – Peter Karlsen Feb 19 at 9:54
  • \$\begingroup\$ It's in the post. My plan is to write up how I used these components to create a data logger using the pico, a few AA batteries and a temperature sensor. Should be quite a fun project. I'm currently also investigating how to use ultra low power sleep mode, but that's outside of the scope of here I think. \$\endgroup\$ – John Hunt Feb 19 at 16:01
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    \$\begingroup\$ I can confirm in practice this diode works perfectly :) \$\endgroup\$ – John Hunt Feb 25 at 20:06

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