Behind The Scenes: Choosing Key Specs For The New Octopart UI

You may have noticed the all new Octopart UI we launched a few weeks ago. One of the major changes we made was adding new key specifications at the top of the search page. These attributes have been chosen to enable you to find and discover the part as fast as possible. For ceramic capacitors, for example, you’ll now find Capacitance, Dielectric, Mount, Case / Package, Voltage Rating (DC), Tolerance and Height at the top. For ADCs, you’ll find Number of Bits, Sampling Rate, INL and DNL among other filters as shown below:

                                    Key specifications on top of new search page

In this blog I am going to dig deeper into our process of selecting and displaying the most relevant specs for each category at the top of search results page. Octopart has been great at finding you parts for exact MPN searches. However, there are several times in the component discovery and selection process that you might not know the exact MPN for a part. With the new update, we wanted to help you find parts in these cases too.  This is better shown in a flow chart below. We wanted to improve the Octopart experience for the right side of this flow chart:

                              Component Selection Process

There were a few goals in choosing the new key specifications:

  1. Ability to apply most important specs filters at the top of every search result page.
  2. Ability to sort by most common values in each specification.
  3. Ability to learn which specifications are important for each category.

The process of selecting the relevant attributes to show at the top was a slow iterative process which needed a lot of research. While selecting these attributes, we wanted to make the experience of discovering parts as fast as possible while at the same time letting you have the option to choose any way to filter the parts. This was a trade-off and we wanted to choose only the most important attributes to show for each category. We had to dig into our electrical engineering experiences of discovering parts, our conversations with other electrical engineers as well as datasheets to help along the way.   Let’s take a few examples to elaborate this more and also see how we worked to achieve the 3 goals mentioned above:

I. Choosing Key Specs for Ceramic Capacitors:

For ceramic capacitors, we chose key specs based on main physical specifications such as Mount (surface-mount or through-hole), Case/Package, and height. Height became apparent to us as a key filter after talking with engineers who work on lots of DFM-focused PCB projects. We also looked at the technical requirements to pick the key specs. We chose dielectric as one of the key specs as it shows the variation of capacitance with temperature. NP0/C0G capacitors are accurate and have a tolerance of 30ppm/K but are only available till a few nF. X5R and X7R have a tolerance of +/- 15% over their temperature range. More about this research can be read in our blog “How to Select a Capacitor”.

We added tolerance as it characterizes how much the capacitance varies from rated values.  We also picked voltage rating(DC) as it shows the maximum DC voltage that a capacitor can handle. This is particularly important for ceramic capacitors as they are known to have large voltage coefficients — they have a large decrease in capacitance values as the applied voltage approaches the rated voltage.

With our latest UI, you can access any of the main filters really fast at the top of the search page. But you can also access all the other available filters with a simple dropdown as shown below:

               Access key specs at top — but access all specs with a dropdown

We used a similar approach to choose key specs for passive components including resistors, inductors, and crystals.

II. Choosing Key Specs for Op Amps:

For op amps we chose the key specs based on physical specifications such as the Case/Package, number of pins, and number of circuits. These affect the size of the PCB and the routing complexity. Next, we considered some of the main technical requirements:

a) Speed of op amp’s response:
This is characterized by Slew Rate and Gain Bandwidth Product. Slew Rate is the maximum rate at which the op amp can respond to a large change in input signal. Gain Bandwidth Product is the maximum bandwidth an op-amp can have. This occurs at a closed loop gain of 1. It is the maximum speed that an op-amp can operate at – and is very important to its performance. Product of gain and bandwidth is a constant- an op-amp with 10MHz GBW will only have a bandwidth of 1MHz at a closed loop gain of 10.

b) Noise rejection by op amp:
This is characterized by Power Supply Rejection Ratio (PSRR) and Common Mode Rejection Ratio (CMRR). PSRR refers to the ability of the op amp to suppress variations in power supply. CMRR refers to the ability of the op amp to suppress common-mode signals that appear simultaneously in both inputs. A rejection ratio of 60dB means 1000:1 rejection ratio, so 1V ripple at power supply would translate to output voltage having 1mV ripple. These ratios are important to understand how well the op-amp rejects external noise.

c) Power consumption:
This is characterized by supply voltage and supply current which have both been added in key filters as well.You can switch to “Specs” view at the top of the search result page to see all the key specs displayed together under “Most Relevant” section. This allows for a rapid discovery of new parts.

You can switch to “Specs” view at the top of the search result page to see all the key specs displayed together under “Most Relevant” section. This allows for a rapid discovery of new parts.

                Key specs shown in “Specs” view under “Most Relevant” section

We used a similar approach to choose our ICs including micro-controllers, logic ICs, voltage regulators and more.

III. Choosing Key Specs for ADCs: 

For ADCs, we not only chose the Sampling Rate to characterize the speed of the ADC but also the Integral Nonlinearity (INL) and Differential Nonlinearity (DNL) to fully characterize the nonlinearities in the ADC. Our goal was also to enable learning about which specifications are important and which values among them most important.

In ADCs, opening the modal for INL and sorting by results enables you to see that 1LSB and 2LSB are most common values for INL. If the ADC you pick has lower INL than this, it’s better than most of the ADCs.                  

Sorting by Results shows which values are most common

We chose key specs for all categories to enable you to apply filters as fast as possible but also have access to every spec if you wanted to, without any cumbersome scrolling. We also added the ability to sort by results to see most common value to make it easy to build a good mental model while choosing a part. Finally, we chose key specs so that you can learn more about the subcategory of the part you are interested in.

This took a considerable effort from our team – we wanted to make sure you can quickly discover parts on Octopart. We’d greatly appreciate if you could let us know what you think, drop us a comment below or chat with us in Slack room!

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