(for the help of Americans, "chips" mean "french fries" in the context of asking someone if they want "fries with that", but also mean "microchips" in context of electronics, sorry to have to explain that)
For a lot of my little PCB designs I need a voltage regulator, something to provide a clean 3.3V DC power for things like an ESP32, which means over 0.5A peaks for WiFi. In this case I have a nice PCB footprint using an LMR16006 which is 600mA at 3.3V, and has proved very reliable and easy to use.
There are many reasons for picking this, even though a slightly pricey solution. For a start it is a leaded chip so can be hand soldered. To be honest I am doing things using solder paste and a stencil much more now, so far less critical. But it is small - the whole footprint for the regulator is small.
Some time ago I got 100 off of the parts and put in a draw and have used on various boards, but I am running out. It is only a few pounds for the parts. What none of us knew is chips would become somewhat hard to get all of a sudden. Had I had any clue I'd have got several hundred and even kept them on tapes so could be used for production. Hindsight.
So now I am stuck. I have limited supplies and nobody has stock until late 2023 now. So I need to find an alternative. Something small and easy to use. Something available that won't run out! Something offering at least 600mA of 3.3V. Something with a nice wide input voltage range. Something easy to hand solder, or at least easy to solder paste and cook by hand. Also, as some boards are battery based, we want very low idle current, which this manages quite well and automatically.
I saw a LTC7103 suggested by someone - way overkill, but very cool. Also rather pricey. I looked a little while ago, and thought that it was good that you can still get them. Today I thought I would try this out, and get some, and make some boards, only to find Mouser have 7 of them, and a silly price, and no more until August at the soonest.
So I need to find something else. I am not an electronics engineer, honest. I know that whatever I get means new PCB layouts for various boards. I am starting to get a feel of how much hassle this all is right now. Oh! to be back in the "normal" days of next day whatever chips you want from a range of suppliers.
I expect I'll pick another solution some time soon, and make some boards, and maybe even hoard a few hundred of whatever I pick!
Of course the same is happening to the new FB9000 FireBricks, which are also waiting on chips. All fun and games.