In the electronics industry, looking for parts can sometimes be quite aggravating. One distributor may have the series you’re looking for but not the specific device while another distributor might have the device but not the supporting parts needed for your design. Additionally, there may be problems with having the components in-stock when they are needed.
Digi-Key Electronics takes great pride in having one of the industry’s largest varieties of parts in-stock and ready for shipment on the day an order is placed. Digi-Key’s part search database is a powerful tool for finding the components you need quickly. However, there may be times when looking for parts becomes a bit frustrating, especially when there are a lot of similar parts to choose from.
This article will provide some tips and tricks, even some hidden ones, which can be used to make Digi-Key’s parts search even easier to use to find whatever you are looking for quicker and easier. Please note that the examples presented here were accurate as-of the date of this posting.
General Searching for Parts
Digi-Key’s part search is designed to help you find the parts that fit the parameters required by your design in a streamlined manner. For instance, say you’re looking for through hole resistors. Start by entering “resistors” into the “Part Search” box on top on the page (see results in Figure 1).
Figure 1: Search results for “resistors”.
This shows all resistors in the parts database. However, we’re looking for through hole resistors. So clicking on “Through Hole Resistors” brings us to a page that shows all through hole resistors available.
As can be seen in Figure 1, there are over 281,000 items listed in through hole resistors. Fortunately, there are parameter filters we can use to narrow this down to a list that is more manageable (Figure 2).
Figure 2: “Through Hole Resistors” parameter filters.
The best way to use these filters is to select the most important parameter first; in this case it would most probably be “Resistance (Ohms)”. You can select more than one parameter value in a field by simply holding down the “Ctrl” key on your keyboard while clicking, or if selecting a range you can select the first value, scroll to the second value and click it while holding down the “Shift” key. (Alternatively, you can select a range by clicking and holding on the first value and dragging your mouse through the list to the end value of the range you’re looking for.) After all values are selected, just click on the “Apply Filters” button to see the results.
After the most important parameter filter is applied, move on to the next most valuable parameter filter and repeat until all parameters you want to filter are complete. It is recommended that you filter by one parameter at a time because cases could arise where filtering by multiple parameter filters simultaneously will result in zero parts that meet all of the selected parameters.
Stepping Through an Example
Let’s step through a real example. We want to find an N-Channel MOSFET rated for at least 50 amps and 85 volts in a through hole TO-220 package. If we enter “MOSFET N-Channel 50A 85V Through Hole TO-220” in the search box, the result is three obsolete parts (Figure 3).
Figure 3: Search results for “MOSFET N-Channel 50A 85V Through Hole TO-220”.
This search string is too restrictive to obtain the results we’re looking for (mainly because of the specific current and voltage ratings). Let’s start over and use the parameter filters to see if we can find other parts that will meet our specification.
When starting a general search where you want a choice of parts to compare, it’s always best to start out as general as possible and filter down until you reach a reasonable number of results to work with. In this example, we’ll start by entering “MOSFETs” in the search box (note, Digi-Key’s part search is not case sensitive). This results in 51,795 items as shown in Figure 4.
Figure 4: Search results for “MOSFETs”.
We are looking for single MOSFETs, so we click on the “Transistors – FETs MOSFETs – Single” link. The page we come to then shows that there are 40,935 items left to choose from (Figure 5).
Figure 5: Search results for “MOSFETs” in the “Transistors – FETs MOSFETs – Single” family.
Now it’s time to start using the parameter filters. First we’ll choose the “FET Type”. Since we are looking for an N-Channel MOSFET, we’ll select all of the FET types that match the requirement (Figure 6). One thing to note when looking at the parameter values is that sometimes the values “*” and “-“ appear as shown in many of the figures in this article. A “*” indicates that the value has not been entered yet, usually for newer parts. A “-“ indicates that the value was not found on the data sheet.
Figure 6: Select all N-Channel FET Types.
After clicking the “Apply Filters” button we are left with 33,342 items. Next let’s narrow it down a bit further by scrolling to the right in the parameter filters to find the “Mounting Type” parameter. Since we are looking for a through hole part, we select that (Figure 7) and click on “Apply Filters”.
Figure 7: Select “Through Hole” mounting type.
Now we’re down to 8,436 parts. The next filter we will use is the “Package / Case” parameter. Scroll to the right in the parameter filters to find it and select all of the TO-220 options available (Figure 8) and “Apply Filters”.
Figure 8: Select all “TO-220” options available for “Package / Case”.
This cuts the available parts down to 4,102. The next thing we’ll filter for is our voltage rating. Since we are looking for a MOSFET with a rating of at least 85 volts, we’ll select that and include all of the parts with ratings up to 120 volts for some extra margin (Figure 9) and “Apply Filters”.
Figure 9: Select a voltage rating range from 85 V to 120 V.
There are still 460 parts left to choose from. Finally, we will filter by our last parameter, current rating. Our specification is for 50 amps, but let’s give ourselves a bit of a cushion and select all those MOSFETs rated for 50 to 60 amps (Figure 10) and “Apply Filters”.
Figure 10: Select a current rating range from 50 A to 60 A.
We are finally down to just 43 parts, a manageable number to sort through. However, since we want the part quickly, we can reduce this even further by checking the “In stock” check box and clicking on “Apply Filters” (Figure 11).
Figure 11: Final filtered results after checking the “In stock” box.
Instead of the three obsolete parts we saw in our original search, we now have 21 options to choose from. These results can be sorted by using the up and down arrows at the top of the column you would like to sort by (Figure 12).
Figure 12: Part search results sorted by “Vgs(th)(Max)@Id”.
One thing to note when using the parameter filters, if you apply a filter but later decide to remove it, all you have to do is click on the checked box in the “Applied Filters:” line. This allows you to modify the filter choice or just not use it for your search.
Hidden Search Secrets
Unknown to most users of the Digi-Key part search engine is that it is possible to use Boolean logic in a search string. The Boolean operands AND, OR, and NOT are supported.
For an AND statement, simply put a space in between each parameter entered in the search string. You could also use “.and.”, but that adds a lot of typing to get the same result as a simple space.
When you want an OR statement, insert a “|” (shift \ on a standard keyboard) or “.or.” between each operand you want ORed. The user has to keep in mind that using an OR statement could greatly increase the number of search results.
Similarly, for a NOT statement, insert a “~” or “.not.” between the operands. This is particularly handy when you want to exclude something in your search results. For instance, if you search for “antennas ~ accessories”, the results would not include any parts with the word “accessories” in any of its parameter fields.
Another search tip, which is common to most search engines, is that you can search for an exact phrase by putting it in quotes. An example of this would be searching for – microcontroller “32 x 8” – which yields 201 parts while the same search without the quotes would yield 33,926 parts.
Sometimes Less is Better
For those of you that use Digi-Key’s part search regularly, you know that you can find the part you’re looking for very easily if you know either the exact Digi-Key part number or the manufacturer part number. However, if there is just one character wrong or missing, your search may not turn up anything. Here’s where searching with a partial part number becomes very helpful. For example, say you’re looking for a PIC24F16KL402-I/ML microcontroller from Microchip but for some reason you think the part number is “PIC24F16K402-I/ML”, omitting the “L” after the “K”. The search result would give you a page that states there were no results and to make sure the part number was entered correctly (Figure 13).
Figure 13: Parts search result with incorrect part number.
After looking at the part number, you don’t see anything wrong, so you could assume that the part isn’t in Digi-Key’s parts database. However, you know that you saw the part there the last time you searched for it. One simple solution is to start making the part number shorter in the search box. For this example, deleting one character at a time from the end of the part number in the search box and redoing the search after each deletion will not result in finding any parts until you get down to “PIC24F16K402”. This search results in two parts, both non-stocking and not the parts you’re looking for. Continuing to shorten the part number even more, you finally get to a page that shows there are “117 items” found in “Embedded – Microcontrollers” (Figure 14).
Figure 14: Parts search results for “PIC24F16K”.
Clicking into the “Embedded – Microcontrollers” link along with checking the “In stock” check box will reduce the number of parts to 38. This makes it fairly easy to find the part you were originally looking for.
Searching Within Search Results
Digi-Key added the capability in early 2016 to “Search Within Results” after the initial search results are returned (in the first field in the gray section under the total “Results:” count returned). This allows the refining of the search based on the previous search results instead of starting a new search.
Let’s go through another quick example to demonstrate the usefulness of this feature. In this example we’ll search for a 16-bit microcontroller with USB and UART connectivity and 50 to 55 I/Os without caring who the manufacturer is. First search for “microcontrollers” and then click the “Embedded – Microcontrollers” link since that is what we’re looking for (Figure 15).
Figure 15: Search results for “microcontrollers”
This returns a results page with over 58,000 parts, far too many to sort through to find parts that would fit your specifications. To narrow this down, we’ll use a few of the filters without showing every step like was done in our previous example. We can easily filter for 16-bit (“Core Size” filter) and 50 to 55 I/Os (“Number of I/O” filter). Next we’ll filter for “Active” parts (“Part Status” filter) and check the “In stock” check box and click on the “Apply Filters” button. This brings the total results down to less than 400 parts (Figure 16).
Figure 16: Search results with filters applied
This is still far too many to sort through. We are still looking for parts that have USB and UART connectivity. Looking through the “Connectivity” filter we see that we can’t choose just USB or just UART. All connectivity filter parameters contain multiple entries. Here’s where the “Search Within Results” comes in handy. Entering “USB UART” in this box and pressing “Enter” on your keyboard or clicking the magnifying glass next to the field will return about 100 parts (Figure 17).
Figure 17: “Search Within Results” for “USB UART” search string
This is a much more manageable number of parts to look through than the initial 58,000. Of course, you could always apply more filters or more “Search Within Results” at this point to further narrow down the selection.
Additional search tips
There a few other tidbits of information to keep in mind when using the Digi-Key part search engine:
- All search terms are automatically wild carded. In other words, when “LED” is searched for, most of the top results you get are in the expected optoelectronics area. However, you also get results in USB Cables, to name just one, because “LED” is contained in the word “SEALED” found in the “Description” field.
- The search engine does not automatically look for spelling variations. For example, searching for “pressure sensors” will yield fewer results than searching for “pressure sensor”. It is best to use singular search terms to obtain the most inclusive results.
- All searches are text based and not numerically aware.
- When looking for a 0402 resistor, the best results are obtained by searching “402 resist” and relying on wildcarding.
- Finding a .2 inch terminal block can be found searching for “.2 term block”. However, searching for “.2” term block” will yield different results since most of the measurements entered into the database are listed as 0.200” and these will not be found.
- Keep in mind that the terms “inch” and “foot”, along with their associated abbreviations “in.” and “ft.”, are rarely found in the Digi-Key parts database. Best practice is to not use these terms and narrow down these parameters when you start filtering your results. If you want to use these in the search string, using double quotes (“) for inches or a single quote (‘) for feet will get you the best results.
Even though Digi-Key’s part search engine is easy to use and get results quickly, there are some methods and tricks you can use to see and compare more parts that will be within your specifications. So if you get frustrated searching for parts, keep in mind the methods discussed in this article may help you find the parts you need and present you with more options to consider for your design.