10 ms·

Firstly, well done on making your first PCB - and it looks like you've done a pretty good job besides! > I passionately hate Digikey’s search interface. It is

by kiwih 3y ago

Firstly, well done on making your first PCB - and it looks like you've done a pretty good job besides! > I passionately hate Digikey’s search interface. It is shockingly bad at having the right metadata for filtering to be effective. I disagree wholeheartedly. Digikey has amongst the best interface for parts searching that I have ever used. What exactly about the interface do you dislike?

fake-name 3y ago
100% this. I shop almost exclusively on digikey at work when I can because their search is *so much* better then everyone else's. It's certainly not great, but it's definitely the best of any electronics component vendor by a large margin. Mouser's filtering facilities are dramatically worse.
- doubloon 3y ago
  i had no idea how to use digikey until I watched Lady Ada do it on an Adafruit video tutorial. compared to a lot of other web interfaces, its not exactly intuitive but once i got the hang of it its nice.
mitthrowaway2 3y ago
It's probably the best there is, but still leaves a lot to be desired. For example, let's say you want to choose, say, a power MOSFET to handle certain large current. In your design you could use one, or you could use multiple in parallel. Naturally, in this case you want to sort parts by amps per dollar, but you can't sort or filter by mathematical functions of combinations of parameters. So first you have to assume you'll use one mosfet, and find the best one; then repeat assuming you're paralleling two, and so on... Same if you're looking for capacitors and so on. You can rank by dollars, you can rank by Farads, but you can't rank by Farads/dollar, or stored energy (farad-volts-squared) per dollar etc. You could perhaps export to excel and do the search yourself, but sometimes that's not easy. You can specify value (6 mH) and tolerance (+-10%), but not joint values-and-tolerances. So if you really need at least 6 mH minimum, you technically want to search >6.7 mH +-10% and >6.3 mH +-5%, etc, but that's extra work. Sometimes the parameter you care about simply isn't available in Digikey's filter, because it's a little obscure like... high-frequency CMRR, or something. So you have to dig into each part datasheet one at a time. That's not really Digikey's fault though; they've tried their best to guess the parameters that are most important, and nobody else has done better. Where it does get very frustrating is when you need to search through ranges of ranges of values. Like, if your application has a supply voltage that could be between 3.3V and 5V, then you want to filter out parts that require an input voltage higher than 3.3V, or are damaged by an input voltage below 5V. But there's rarely an easy way to do this; often Digikey has one column containing value ranges like "1 - 4V", "1 - 4.1V", "1 - 4.2V"... "1.1 - 4V", "1.1 - 4.1V", and so on. Some of their filters have gotten smarter, but many are still like this, and it takes a long time to go through and select all possible acceptable parts and reject all inadmissible ones. So to save time you end up just guessing at a few likely ranges of values, but then later you discover that there's one really good part that's perfect and cheap but it can tolerate voltages all the way up to 25V for some reason, and you just filtered it out early on because it would have taken too long to scroll that far down. Searching for connectors can be very frustrating, because there's usually no easy way to look through related parts in a connector family, like to find matching male and female crimp pins and their respective housings. A lot of frustrations like that are very common, especially when approaching a design from a blank slate.
- quailfarmer 3y ago
  I think you’re in an uncanny valley where you want to have those powerful search features, but haven’t realized you probably wouldn’t actually use them. For ubiquitous passives, the DK search has all the relevant requirements, and then I’m just picking the manufacturer I have a relationship with. The supply chain on a single passive isn’t worth the headache to save a few percent. Aside from passives though, you’re never going to get exactly what you want from any reasonably bounded database. For a FET you’re trading footprint, thermal impedance (both up and down), SOA, parasitic capacitances, turn on times. When I’m picking a key part, I’ll start with a DK search, get a sense for which MFGs are leading the field, make a list of 10 or so parts that look promising, and go through the material on each, filling out my own spreadsheet as I go. That’s even more true for anything with digital logic, where it wouldn’t be possible to sort by the enumerated features in a meaningful way.
  - mitthrowaway2 3y ago
    I know I'd use them, because I've had to script them myself. Often this comes into play not for random passives, but for key cost-driving components: a big pulse-capable capacitor (eg. for spot-welding), power mosfet, a precision differential amp, and so on. You can end up in a design space where the one-piece component you want is super expensive and rare, but if you make the same thing out of two or three or twenty parts, you can use cheaper and more common components, and benefit from higher volume pricing to boot. Gate capacitance is a great example because if I'm considering MOSFETs in parallel I'll want to bound the sum of their capacitances. Again, easy to do with expressions, hard with DK's interface. What other sites do (eg. TI) is have a bunch of extra search fields but make them collapsible.
    - sheepshear 3y ago
      Optimizing Digikey prices is a bit of an oxymoron, isn't it? They're expensive because they're fast. Also, specs aren't well standardized between manufacturers. TI has some good videos explaining what their power MOSFET specs mean and how those definitions vary across the industry. Automatic optimization can only get you so far.

by kiwih 3y ago

fake-name 3y ago

100% this. I shop almost exclusively on digikey at work when I can because their search is *so much* better then everyone else's. It's certainly not great, but it's definitely the best of any electronics component vendor by a large margin. Mouser's filtering facilities are dramatically worse.

doubloon 3y ago
i had no idea how to use digikey until I watched Lady Ada do it on an Adafruit video tutorial. compared to a lot of other web interfaces, its not exactly intuitive but once i got the hang of it its nice.

mitthrowaway2 3y ago

It's probably the best there is, but still leaves a lot to be desired. For example, let's say you want to choose, say, a power MOSFET to handle certain large current. In your design you could use one, or you could use multiple in parallel. Naturally, in this case you want to sort parts by amps per dollar, but you can't sort or filter by mathematical functions of combinations of parameters. So first you have to assume you'll use one mosfet, and find the best one; then repeat assuming you're paralleling two, and so on... Same if you're looking for capacitors and so on. You can rank by dollars, you can rank by Farads, but you can't rank by Farads/dollar, or stored energy (farad-volts-squared) per dollar etc. You could perhaps export to excel and do the search yourself, but sometimes that's not easy. You can specify value (6 mH) and tolerance (+-10%), but not joint values-and-tolerances. So if you really need at least 6 mH minimum, you technically want to search >6.7 mH +-10% and >6.3 mH +-5%, etc, but that's extra work. Sometimes the parameter you care about simply isn't available in Digikey's filter, because it's a little obscure like... high-frequency CMRR, or something. So you have to dig into each part datasheet one at a time. That's not really Digikey's fault though; they've tried their best to guess the parameters that are most important, and nobody else has done better. Where it does get very frustrating is when you need to search through ranges of ranges of values. Like, if your application has a supply voltage that could be between 3.3V and 5V, then you want to filter out parts that require an input voltage higher than 3.3V, or are damaged by an input voltage below 5V. But there's rarely an easy way to do this; often Digikey has one column containing value ranges like "1 - 4V", "1 - 4.1V", "1 - 4.2V"... "1.1 - 4V", "1.1 - 4.1V", and so on. Some of their filters have gotten smarter, but many are still like this, and it takes a long time to go through and select all possible acceptable parts and reject all inadmissible ones. So to save time you end up just guessing at a few likely ranges of values, but then later you discover that there's one really good part that's perfect and cheap but it can tolerate voltages all the way up to 25V for some reason, and you just filtered it out early on because it would have taken too long to scroll that far down. Searching for connectors can be very frustrating, because there's usually no easy way to look through related parts in a connector family, like to find matching male and female crimp pins and their respective housings. A lot of frustrations like that are very common, especially when approaching a design from a blank slate.

quailfarmer 3y ago
I think you’re in an uncanny valley where you want to have those powerful search features, but haven’t realized you probably wouldn’t actually use them. For ubiquitous passives, the DK search has all the relevant requirements, and then I’m just picking the manufacturer I have a relationship with. The supply chain on a single passive isn’t worth the headache to save a few percent. Aside from passives though, you’re never going to get exactly what you want from any reasonably bounded database. For a FET you’re trading footprint, thermal impedance (both up and down), SOA, parasitic capacitances, turn on times. When I’m picking a key part, I’ll start with a DK search, get a sense for which MFGs are leading the field, make a list of 10 or so parts that look promising, and go through the material on each, filling out my own spreadsheet as I go. That’s even more true for anything with digital logic, where it wouldn’t be possible to sort by the enumerated features in a meaningful way.
- mitthrowaway2 3y ago
  I know I'd use them, because I've had to script them myself. Often this comes into play not for random passives, but for key cost-driving components: a big pulse-capable capacitor (eg. for spot-welding), power mosfet, a precision differential amp, and so on. You can end up in a design space where the one-piece component you want is super expensive and rare, but if you make the same thing out of two or three or twenty parts, you can use cheaper and more common components, and benefit from higher volume pricing to boot. Gate capacitance is a great example because if I'm considering MOSFETs in parallel I'll want to bound the sum of their capacitances. Again, easy to do with expressions, hard with DK's interface. What other sites do (eg. TI) is have a bunch of extra search fields but make them collapsible.
  - sheepshear 3y ago
    Optimizing Digikey prices is a bit of an oxymoron, isn't it? They're expensive because they're fast. Also, specs aren't well standardized between manufacturers. TI has some good videos explaining what their power MOSFET specs mean and how those definitions vary across the industry. Automatic optimization can only get you so far.