On the Package page you will chose the type of package you are creating by specifying the general characteristics of the package, the shape of the package, and the detailed dimensions of the body of the part.
Recently added package types: Cylinder or Can, Disk Button, Flange Mount, and In-LIne Package.
Viewing as you Build
- Data is entered on the left side of the screen and the result is displayed on the right side.
- Zoom in on the right side image by scrolling on the mouse wheel up (zoom in) or down (zoom out).
- To move the image use SHIFT+ L Click on the mouse. Depress and hold, move mouse about the screen.
- Reset the window by selecting Reset Preview at the top of this window.
- When entering terminal numbering you can zoom to the area of the part by selecting the magnifying glass
Footprint Creator- Package Outline
At the top of the page near the picture of your component, you will find a link to your component's datasheet (Adobe icon). Open this up in a separate browser window to reference the package dimensions as you progress through the wizard.
Also, if you hover your cursor over the under Package Outline, you will be shown a reference to the JEDEC standard that describes the terminology used to describe any component's features. If there is a difference between the JEDEC definition, versus the WiKi definition, the JEDEC definition applies. To the right, you will see a 2D model of your component. At this point, you will notice that the 2D model does not have any specific dimensions and has no terminals. As you step through the wizard, you will be filling in these details and in turn refining the model.
Choose your Package Outline type.
- Array Type- Package with rectangular or square body with perpendicular sides.
- Chip Scale Package- Package no more than 1.2X the area of the internal die size.
- Flatpack- Surface mount package with terminals parallel to the seating plane.Terminals can be on 3 or 4 sides.
- Grid-Array- Package that has terminals in a matrix on the bottom of the package and within the package outline.
- Long Form- Cylindrical or tubular package with terminal endcaps or axial terminal wires.
- Microelectronics Assembly- Unpackaged microcircuits and/or packaged microcircuits on a packaging interconnect structure.
- Small Outline- Surface-mounted package with terminals projecting parallel to the seating plane.
- Connector- Package that joins/separates two PCB structures.
- Discrete- Resistor, Capacitor, Inductor, Transistor or Diode.
- Switch- Package that controls the flow of current.
If you select Switch, additional package outlines will be offered such as Push-Button, Rocker, Rotary, Slide, Tactile and Toggle.
We will use a specific example to explain the process and how to fill in the details to create your footprint.
- The first example is Small Outline part BC847BV.
- Other examples can be found at Custom Footprint Examples.
Once you have chosen your Package Outline type, you can move on to choosing your general specifications such as Unit-of-Measure (UOM), Mounting Preparation, Body Direction, Package Shape, and Dimensions. If the datasheet provides dimensions in Metric and Imperial units, then Metric is preferred.
The wizard will help make selections for you throughout the process. In the case of the Mounting Preparation, Small Outline package types will not require prepping prior to mounting. Therefore, the only option available for Small Outline is Straight Mounted preparation. Similarly, Small Outline devices are always placed in the Horizontal direction on the board, so you are not given the option to select Vertical. Also notice that if you hover your cursor over the throughout the wizard, a detailed description is presented.
Next you will select your package shape. Rectangle is the only package shape available for Small Outline devices.
Next you will choose the dimensions for your component using the dimensions specified in your component Datasheet.
- Enter all of the dimensions provided in the datasheet.
- Do not compute dimensions not shown in the datasheet. These are extrapolated from the known items.
- Use dimensions from the bottom side in the datasheet as well as the bottom side terminal numbering.
- Nominal is sometimes referred to as Typical as in the datasheet example below.
- Nominal dimension will be computed by PartQuest if it is not provided in the datasheet.
- Standoff is the amount of space between the board surface and the bottom of the part body. In this example the part sits directly on the board surface so the standoff is zero.
- Body Height is the height of the actual part body.
- Part Height is the height from the board surface to the top of the part including the standoff distance.
- Dimension1 is typically the x dimension. Note the X/Y axis in the left corner of the 2D image.
- Dimension2 is typically the y dimension. Note the X/Y axis in the left corner of the 2D image.
Example of Small Outline Datasheet:
To determine the dimensions to input, find the dimensions chart in your components Datasheet. Note that the dimensions that you provide are those of the package and not the actual footprint.
Enter the dimensions provided in the datasheet. Datasheets vary in how they provide this information. For example, you may get the nominal plus minimum and maximum values of a dimension. An alternate method is to provide nominal dimension with a positive and negative tolerance. PartQuest will create the footprint for you using the package dimensions you provide. If any required information is missing, PartQuest will let you know what dimension is required once you continue to Terminals.
In our Small Outline example, Dimension1 refers to H and Dimension2 refers to B on the datasheet above. Body Height refers to K and since standoff is 0 Body Height and Part Height are identical.
Notice that the right side shows a 2D model of your component in a top down view with all of the input values.
For this part, select Rectangle as the Package Shape.
Once you have entered your values, you can use the 2D model to insure that your dimensions have been entered correctly. Now click the Continue to Terminals button directly underneath your Dimensions table.
Continue to Terminals.
See other Custom Footprint examples under Custom Footprint Examples.