I’ve been building up a circuit that’s based on the UBW32 for a while now but I’m not sure where to find the right parts. I can find the part in the Sparkfun Eagle library and I can build the circuit and board without incident but when I head over to Digikey, I get lost in the swaths of similar but slightly different parts. I doubt ordering one each of 20 or so different 3.3 volt surface mount voltage regulators and trying each one in turn is really the right way to do it.
Is there a guide somewhere on finding the “right” parts? Have I just missed something along the way?
This is the last hurdle I have before really getting to business on a bunch of projects of mine and help would be really wonderful!
When designing a board, I start by selecting the parts, and then create the models if needed. If you are working straight from the UBW32 design, according to the comments, the regulator is a FAN1117A. Digikey has the same parts available from other vendors as ZLDO1117GTA or LD1117ASTR (among others).
Mike’s right on the target here. None of the parts (except for the CPU of course) on the UBW32 are ‘critical’, in the sense that any 1117 regulator (or even a LM317) will work just fine.
For most parts, multiple manufactures will make the same part, usually in the same footprint, so you have lots of choices at DigiKey.
Here’s are the keys:
Getting the footprint right - if you use a footprint that doesn’t match the part you buy, you’re probably going to be hurting. Manually checking some dimensions in the Eagle part with the actual datasheet for the part you buy is the best way to go here.
Comparing basic parameters of the parts. For example, if a BOM calls out a particular regulator, and that regulator has a 35V max input voltage, don’t buy a similar regulator with a 20V max input voltage if you expect to run with 30V input. So when you’re subbing parts, you have to understand just enough about the circuit to know what the important parameters are.
What’s the worst that can happen? You try it out and it doesn’t work, so you get to have some fun and learn somethings by debugging it.
I constantly find myself in that situation. I spend an awful lot of time investigating different parts and whittling them down. Sometimes deal-breakers on important parts force me to revisit previous “ok, go with this one” selections.
I’m guessing with experience you’ll find the parts you like using for circuit glue (like voltage regulators) for which you always wind up reaching.
Thank you very much for the replies. It seems like just jumping down the rabbit hole is a big part of it to some extent I’ll pull out the last schematic I was working on and revisit it with these ideas in mind.
I’ll pull out the last schematic I was working on and revisit it with these ideas in mind.