Chip Resistor Footprint Template
- Begin by opening the Ultra Librarian software. Once the screen below is shown, click “Create New Footprint”.
- A list of Lead Type and Arrangements will appear. Click “Chip”.
- The two main chip categories will branch out beneath “Chip”. Click “All Other Chips”. A list of all the ____ Templates will appear in the box below.
- Since in this case we are building a resistor, choose the “*_ADI’s Res, smt, calculated, Chip” template. Verify you have chosen the correct template by:
- Reading the full name and description in the upper right corner of the window.
- Revising the part schematic on the right side of the window. You may click on the image to shift between different images showing different schematics and/or pin diagrams.
If all of this corresponds with the part you want to build, continue by clicking “Select to Build”.
5. This screen allows you to enter all the measurements to create the footprint. A few things to notice:
- At the top of the screen, the name of the footprint is shown. This is a generic, auto generated name; “RC” indicates that it is a resistor, while the numbers correspond to the measurements of the footprint.
- You may edit this name in the “Pattern Name” box on the top left part of the window.
- For this case, make sure to leave the footprint name as is; to do so, do not enter anything in the “Pattern Name” box.
Click on “View Input Details” to familiarize yourself with how the measurements you enter affect the dimensions of the footprint.
6. The “Input Details” screen will appear, showing how the dimensions in the diagram correspond to the measurements you enter. For chip resistors, all of the measurements you need are found in the “Part Information” section of the footprint template.
For example, “Max Foot Width: FOOT_W” corresponds to the literal width of the resistor’s pin (referred to as “foot” by this software, and usually as “termination” by the part’s datasheet), while also corresponding to the width of the entire body of the resistor; therefore, both widths tend to be the same. Meanwhile, “Max Toe to Toe Length X: LX” corresponds to the length of the entire body; since the pins (the “feet”) are at the ends the resistor, it is the distance from one end (a “toe”) to the other.
7. Upon revising the datasheet for your chosen part, you see that the some or all of the dimensions correspond with the dimensions in the “Part Information” section. In this case, the RPC0603 family of resistors has the following dimensions (Note: Ultra Librarian uses mils by default, so the following numbers correspond to mils):
- LX = L = 0.067”
- LMX = ??? = 0
- FOOT_W = W = 0.035”
- FOOT_L = D2 = 0.020”
- Whenever possible, always choose the bottom termination instead of the top termination, as it is the termination that touches the board.
- Max Component Height Z = H = 022”
- Min Component Height Z = 0”
- It is 0 because the resistor’s body touches the board.
8. Enter the previously obtained measurements in the areas highlighted in the following picture. Click “Apply” or the Enter key to apply the new measurements to the part. Once done, click “Verify”. If there are no errors, click “Done”. And you have finished creating your footprint!