Adding a Description

The final (!!!) step is optional, but it's one last, nice little detail that a future version of you will appreciate as much as anyone else who uses your library: add some basic details about the part to your device's 'Description' field.

What To Include in the Description

While it's entirely up to you, some information you might consider including, spending a few minutes adding key information from the datasheet now can save you a lot of time later when you need to make sure every part on your board meets certain tolerances like temperature range or minimum supply voltage.

As a rule of thumb, you should consider adding the following information in the description field:
  • The recommended supply voltage range for the device (2.3-3.2V in the case of our sensor)
  • The operating temperature for your device (-40°C to 85°C in this case)
  • Any key information about the sensor, such as the output range for the GA1A1S202WP which is 3-55000 lux
  • If you use the same one or two suppliers, you may also find it useful to include the vendor-specific part numbers as well, such as the part code for Digikey, Mouser, Farnell, etc.

Adding Description Data

To add some text to the description field, simply click the 'description' label that is in the bottom-most box by default ...
This will bring up a dialogue box where we can enter our description:
You can use basic HTML formatting for your description, including common HTML tags like 'p' for paragraphs, 'b' for bold, 'ul' and 'li' for lists, etc.

Example

Here is the information included in my part description, taking advantage of some basic HTML tags:
Download: file
<b>GA1A1S202WP</b> - Analog Light Sensor

<p>Technical Specifications:
<ul>
<li>VCC: 2.3-3.2V</li>
<li>Operating Temperature: -40°C to 85°C</li>
<li>Dynamic Range: 3-55000 lux</li>
<li>Peak Sensitivty: 555 nm</li>
</ul>
</p>

<p>Digikey: 425-2789-1-ND<br/>
Mouser: 852-GA1A1S202WP</p>
This results in the following description in the preview window and inside Eagle when we look at this device in detail:

Essential Eagle Skills: Advanced Descriptions

The fact that we can use basic HTML tags, including tables, can be used to our advantage in Eagle for parts with many packages or many variants.

For example, I have literally dozens of SOT23-5 voltage regulators that I use on different boards, depending on the amount of current I need, the output voltage (or voltages!), etc.

To organize all of this information correctly, and allow me to quickly select the right part out of the dozens I have on hand, I created a table for the SOT23-5 VREG device with the key information below:
If you look closely, you'll see that I also added some additional information that may be useful to other people using these parts to calculate the max operating temperature for the regulator.

If this part is likely to be reused a lot, or if you had to look up some specialized information when selecting the right part, including a brief summary of that information in the Eagle device will often come in handy, and a future version of yourself will be very glad for the extra bit of effort you put into things while this information was still fresh in your head!
This guide was first published on Apr 22, 2013. It was last updated on Apr 22, 2013. This page (Adding a Description) was last updated on May 04, 2015.