Working with a Pad Object on a PCB in CircuitMaker

Created: July 30, 2020 | Updated: February 8, 2022

A pad is a primitive design object that are used to provide both mechanical mounting and electrical connections to the component pins. Pads are used for fixing the component to the board and for creating the interconnection points from the component pins to the routing on the board. Pads can exist on a single layer, for example, as a Surface Mount Device pad, or they can be a three-dimensional through-hole pad, having a barrel-shaped body in the Z-plane (vertical) with a flat area on each (horizontal) copper layer. The barrel-shaped body of the pad is formed when the board is drilled and through-plated during fabrication. In the X and Y planes, pads can have a circular, rectangular, octagonal, or rounded rectangular shape. Pads can be used individually as free pads in a design, or more typically, they are used in the PCB Library editor, where they are incorporated with other primitives into component footprints.

Pads are available for placement in the PCB editor in the following ways:

  • Choose Home | Place | Pad from the main menus.

After launching the command, the cursor will change to a crosshair and you will enter pad placement mode.

  1. Position the cursor then click or press Enter to place a pad.
  2. Continue placing further pads or right-click or press Esc to exit placement mode.

A pad will adopt a net name if it is placed over an object that is already connected to a net.

Additional actions that can be performed during placement are:

  • Press the Tab key to pause the placement and access the Pad mode of the Inspector panel in which its properties can be changed on the fly. Click the design space pause button overlay () to resume placement.
  • Press the Alt key to constrain the direction of movement to the horizontal or vertical axis depending on the initial direction of movement. 

Graphical Editing

Pads cannot have their properties modified graphically other than their location.

  • To move a free pad and also move the connected tracks, click and hold then move the pad. The connected routing will remain attached to the pad as it is moved.xxx
  • To move a free pad without moving the connected tracks, choose Tools | Arrange | Move » Move Object, click and hold then move the pad.

If you click and drag a selection rectangle around component pads, they will not select as they are actually child objects of the component. To subselect just the pads, hold Ctrl as you click and drag the selection window.

To clear the selection of (or de-select) the object, use the Esc key. 

Non-Graphical Editing

This method of editing uses the Inspector panel to modify the properties of a Pad object. 

   

During placement, the Pad mode of the Inspector panel can be accessed by pressing the Tab key. Once the Pad is placed, all options appear.

After placement, the Pad mode of the Inspector panel can be accessed in one of the following ways:

  • If the Inspector panel is already open, select the Pad object.
  • With the pad selected, choose View | Schematic | Inspector from the main ribbons.
Press Ctrl+Q to toggle the units of measurement currently used in the panel between metric (mm) and imperial (mil). This only affects the display of measurements in the panel; it does not change the measurement unit specified for the board, which is configured in the Units setting in the Inspector panel when there are no objects selected in the editing design space.

Pad Dialog

Pad properties can also be changed using the Pad dialog, which is accessed by clicking the Edit button under the Pins in Focused Net region in the Netlist Manager dialog (Tools | Netlist | Neliist » Edit Nets).

To toggle the units of measurement used in the dialog between metric (mm) and imperial (mil), press Ctrl+Q.

Layer Selection - click the layer tab to view the desired layer.

Pad Template

  • Template - select a Pad template from the drop-down.
  • Library - displays to which library the Pad template is linked and includes the option to unlink the template from that library.

Location

Values can be defined in either mm or mil units. When entering a value in units other than the current units, add the mm or mil suffix to the value.
  • X - the current X position of the center of the pad relative to the current origin. Edit the value to change the position of the pad relative to the origin.
  • Y - the current Y position of the center of the pad relative to the current origin. Edit the value to change the position of the pad relative to the origin.
  • Rotation - the current pad rotation in degrees. Edit to change the rotation of the pad. Minimum angular resolution is 0.001°.

Hole Information

  • Hole Size - the current hole size for the pad. The value specifies the diameter of the hole (in mils or mm) to be drilled in the pad during fabrication. For a single-layer pad (such as an SMD pad or edge connector), this is automatically set to zero. The hole size can be set from 0 to 1000mil and can be set larger than the pad area to define copper-free mechanical holes. Edit the value in this field to change the pad hole size. 
  • Tolerance - Setting the hole tolerance attribute can help determine the fits and limits of your board. Specify the minimum (-) and maximum (+) hole tolerance for the design.

Choose one of the following options to specify the shape of the hole:

  • Round - specifies a round hole shape (default) for the pad.
  • Square - specifies a square (punched) hole shape for the pad.
  • Slot - specifies a round ended slotted hole shape for the pad.
  • Plated - this option determines whether or not the pad has a plated hole. If both plated and non-plated pads exist in a design, the non-plated holes will be set to use different tools from the plated holes in the NC Drill files.

Separate drill files (NC Drill Excellon format 2) are generated for each hole kind (Round, Square and Slot) as well as for plated and non-plated holes (as defined by the Plated checkbox). This means there can be up to six different drill files generated.

Properties

  • Designator - the current pad designator. If the pad is part of a component, the designator is usually set to the corresponding component pin number. The designator can be up to 20 characters in length and cannot include any spaces. Free pads can include a designator or the field can be left empty. If the designator begins or ends with a number, the number will auto-increment when placing a series of pads sequentially. Edit the value in this field to change the pad designator. Note that multiple pads within the same component footprint can share the same designator if required.
  • Layer - the layer to which the pad is currently assigned. Pads can be assigned to any available layer, Set the Layer to Multi-Layer to define a pad shape on all signal layers.
  • Net - the net to which the pad is currently assigned. Change the net assignment by clicking in the field and choosing a net from the drop-down list. Select No Net to specify that the pad is not connected to any net. The Net property is used by the Design Rule Checker to determine if a PCB object is legally placed.
  • Electrical Type - this field displays the current electrical status of the pad. This status is only relevant for component pads and sets the transmission line characteristics for these pads. Pads can be designated as a Load, Source or Terminator. The Source and Terminator settings are used when a net requires one of the Daisy chain routing topologies. Click the field to change the electrical type from the drop-down list.
  • Pin/Pkg Length - the Pin Package Length is automatically included in the Signal Length calculations that are displayed in the PCB panel. Set the PCB panel to Nets mode to examine or edit the value of the Pin/Pkg Length for the pins in the chosen net.
  • Jumper ID - set this to a non-zero value (range of 1-1000) to indicate that this pad is part of a jumper component footprint. Jumper components can be used on a single-sided PCB when there will be a wire link that physically connects the pads together rather than using tracks to create the connection. The Jumper ID value tells the software which pads to treat as 'connected'. A jumper connection can only be created between the pads within the same component footprint; they must have the same Jumper ID value and must also be assigned the same net. The component must also have its Type set to Jumper. When these conditions are met, a jumper connection is shown as a curved connection line in the PCB editor.
  • Locked - enable to protect the pad from being edited graphically. Lock a pad whose position or size is critical. If you try to edit a primitive that is locked, you will be informed that the primitive is locked and asked if you want to proceed with the action. If this option is unchecked, the primitive can be freely edited without confirmation. Note that the Locked checkbox has no effect on a pad that belongs to a component. If the component is not locked, the pads will move when the component is moved. In this situation, lock the component to prevent accidental movement.

Testpoint Settings

Use this region to define this pad as a testpoint for Fabrication and/or Assembly testpoint file generation. A testpoint is a location where a test probe can make contact with the PCB to check for correct function of the board. Any pad or via can be nominated as a testpoint. When this is done, the component to which the pad or via belongs automatically gets locked.

  • Top - enable this option for this pad to be defined as a top layer testpoint.
  • Bottom - enable this option for this pad to be defined as a bottom layer testpoint.

Size and Shape

The copper area (land area) of the pad is defined by the X and Y Size and the Shape settings.

  • Simple - a simple pad is one whose size and shape are identical on all layers.
  • Top-Middle-Bottom - a Top-Middle-Bottom layered pad supports defining different X and Y sizes and shape for the top layer, for all mid signal layers, and for the Bottom layer, separately.
    • X-Size - the current X (horizontal) size of the pad. Enter a value from 1 to 10000mil. The X and Y size can be set independently to define asymmetric pad shapes. 
    • Y-Size - the current Y (vertical) size of the pad. Enter a value from 1 to 10000mil. The X and Y size can be set independently to define asymmetric pad shapes.
    • Shape - the basic pad shape. Basic pad shapes include Round, Rectangular, Octagonal, or Rounded Rectangle. The basic shape can be manipulated by changing the X and Y size settings to produce an asymmetrical pad shape.
    • Corner Radius - this option is available when the Shape is set to Rounded Rectangle. The value is a percentage of half of the shortest side of the pad, therefore, a value of 0% corresponds to a rectangular pad and 100% to a circular pad.
    • Offset From Hole Center (X/Y) - enter a value to offset the pad land area from the center of the pad hole by this amount.
  • Full Stack - different hole sizes and diameters can be edited at each layer (including all signal layers and planes).
    • Edit Full Pad Layer Definitions - click to open a dialog that provides controls related to pad/via settings for each layer, including pad shape, size, and X/Y location. Full Stack must be selected to access this button.

Paste Mask Expansion

An opening in the paste mask is automatically created by the software that is the same shape as the pad. This opening can be larger (a positive expansion value) or smaller (a negative expansion value) than the pad itself as defined by this setting. Typically, paste mask openings are smaller than the pad, but there are exceptions to this.

  • Expansion value from rule - when this option is enabled, the paste mask expansion for this pad is defined by the applicable Paste Mask Expansion design rule.
  • Specify expansion value - enable this option to override the rule and specify the paste mask expansion value for this pad.

Solder Mask Expansion

An opening in the solder mask is automatically created by the software that is the same shape as the pad. This opening can be larger (a positive expansion value) or smaller (a negative expansion value) than the pad itself as defined by this setting. Typically, solder mask openings are larger than the pad, but there are exceptions to this.

  • Expansion value from rules - when this option is enabled, the solder mask expansion for this pad is defined by the applicable Solder Mask Expansion design rule.
  • Specify expansion value - enable this option to override the rule and specify the solder mask expansion values for this pad.
  • Solder Mask From The Hole Edge - if the expansion value is being specified in this dialog, you also can enable this option to define the solder mask expansion from the edge of the hole instead of the edge of the pad.
  • Force complete tenting on top - the term tenting means to close off. If this option is enabled, the settings in the applicable solder mask expansion design rule will be overridden, resulting in no opening in the solder mask on the top solder mask layer for this pad. When this option is enabled, the Expansion value from rules and the Specify expansion value options are ignored.
  • Force complete tenting on bottom - the term tenting means to close off. If this option is enabled, the settings in the applicable solder mask expansion design rule will be overridden, resulting in no opening in the solder mask on the bottom solder mask layer for this pad. When this option is enabled, the Expansion value from rules and the Specify expansion value options are ignored.

Paste and Solder masks are shown in the negative, i.e. when you see an object on one of those layers, it is actually a hole or opening in that layer.

Editing Multiple Objects

The Inspector panel supports multiple object editing, where the property settings that are identical in all currently selected objects may be modified. When multiples of the same object type are selected manually, an Inspector panel field entry that is not shown as an asterisk (*) may be edited for all selected objects.

PCB Editor object properties are definable options that specify the visual style, content and behavior of the placed object. 

All Pad object properties are available for editing in the Inspector panel when a placed pad is selected in the design space.

 

Properties

  • Designator - this field displays the current pad designator. If the pad is part of a component, the designator is usually set to the corresponding component pin number. The designator can be up to 20 characters in length and cannot include any spaces. Free pads can include a designator or the field can be left empty. If the designator begins or ends with a number, the number will auto-increment when placing a series of pads sequentially. Edit the value in this field to change the pad designator. 
  • Layer - this field displays the layer to which the pad is currently assigned. Pads can be assigned to any available layer. To change the assigned layer, click the field and select a layer from the drop-down. When designing a surface-mount component footprint, set the Layer to Top even if the component is intended to be used on the bottom side of the board. The software will automatically flip the pad's layer when the component is flipped to the bottom side of the board. For a standard through-hole pad, set the Layer to Multi-Layer.
  • Net - use the drop-down to select the net to which this pad belongs. All nets for the active board design will be listed in the drop-down list. If there is no net, click  to jump to a specific net within the design space. 
Pads automatically connect to any internal power planes that are assigned to the same net. The pad will connect to the plane in accordance with the applicable Power Plane Connect Style design rule. If you do not want a pad to connect to power planes, add another Power Plane Connect Style design rule targeting the required pads with a connection style of No Connect. Pads connect to polygon pours in accordance with the applicable Polygon Connect Style design rule.
  • Jumper - this field provides a jumper connection identification number (range of 1 - 1000) to the pad when you are using a jumper connection on the PCB. A jumper connection uses a wire to physically connect pads on a PCB and not using tracks or electrical objects on the board. The Jumper value tells the software which pads to treat as 'connected'. A jumper connection can only be created among the pads within a component footprint. The pads used must use the same Jumper value and must also share the same net. Use the scroll arrows or directly enter the desired jumper connection identification number. Jumper connections are shown as curved connection lines in the PCB editor. The Design Rules Checker will not report jumper connections as unrouted nets.
If it is not physically possible (or desirable) to implement all connections as routing, for example, on a single-sided PCB, jumpers can be used. Within a component footprint, label the pads that are to be connected by a jumper with the same, non-zero, Jumper ID value. Pads that share the same Jumper ID and Net name tell the system that these pins will be connected by a physical jumper during PCB assembly if that component also has a Type of Jumper.

  • (X/Y) - The X and Y axes locations of the pad.

  • Rotation - the rotation of the pad.

Pad Stack 

  • Hide/Show Preview - toggle to show or hide the preview image.
  • Simple - select to choose a simple layered pad. You can define X and Y sizes and shape attributes that are common for all layers of this pad.
    • Shape - this field shows the current basic pad shape. Choices are RoundRectangularOctagonal, and Rounded Rectangle. Basic shapes can be manipulated by changing the X and Y settings to produce asymmetrical pad shapes. 
    • (X/Y) - displays the current X (horizontal) and Y (vertical) size of the pad. The values set the size of the pad and can accept values of 1 to 10000mil. The X and Y size can be set independently to define asymmetric pad shapes. The value can be entered in either metric or imperial; include the units when entering a value whose units are not the current default. Default units (metric or imperial) are determined by the Units setting in the Other region of the Inspector panel in Board mode (accessed when no objects are selected in the design space) and are used if the unit is not specified.
    • Corner Radius - this displays the corner radius of a pad. The pad radius is represented as a percentage of half of the shortest side of the pad. This option is available only if Rounded Rectangle is selected as Shape
    • Offset From Hole Center (X/Y) - enter a value to offset the pad landing area from the center of the pad hole.
  • Top-Middle-Bottom - select to choose a Top-Middle-Bottom layered pad object. You can define X and Y sizes and shape attributes for top, middle and bottom layers for this pad object.
    • Displayed Layer(s) - click on a displayed layer to configure pads for that layer. The selected layer is highlighted.
    • Shape - this field shows the current basic pad shape. Choices are RoundRectangularOctagonal, and Rounded Rectangle. Basic shapes can be manipulated by changing the X and Y settings to produce asymmetrical pad shapes. 
    • (X/Y) - displays the current X (horizontal) and Y (vertical) size of the pad. The values set the size of the pad and can accept values of 1 to 10000mil. The X and Y size can be set independently to define asymmetric pad shapes. The value can be entered in either metric or imperial; include the units when entering a value whose units are not the current default. Default units (metric or imperial) are determined by the Units setting in the Other region of the Inspector panel in Board mode (accessed when no objects are selected in the design space) and are used if the unit is not specified.
    • Corner Radius - this displays the corner radius of a pad. The pad radius is represented as a percentage of half of the shortest side of the pad. This option is available only if Rounded Rectangle is selected as Shape
    • Offset From Hole Center (X/Y) - enter a value to offset the pad landing area from the center of the pad hole.

Paste Mask Expansion

An opening in the paste mask is automatically created by the software and is the same shape as the pad. This opening can be larger (a positive expansion value) or smaller (a negative expansion value) than the pad itself as defined by the Paste Mask Expansion settings. Typically paste mask openings are smaller than the pad but there are exceptions to this. This can be overridden and local values can be defined directly in the Pad dialog if required.

  • Rule - select to have the paste mask expansion for the pad follow the applicable Paste Mask Expansion design rule.
  • Manual - select to override the applicable design rule and specify the paste mask expansion value for the pad. You can then enable and enter the desired measurement. The value can be entered in either metric or imperial; include the units when entering a value whose units are not the current default. Default units (metric or imperial) are determined by the Units setting in the Other region of the Inspector panel in Board mode (accessed when no objects are selected in the design space) and are used if the unit is not specified.

Solder Mask Expansion

An opening in the solder mask is automatically created by the software and is the same shape as the pad. This opening can be larger (a positive expansion value) or smaller (a negative expansion value) than the pad itself as defined by the Solder Mask Expansion settings. Typically solder mask openings are larger than the pad, but there are exceptions to this. This can be overridden and local values can be defined directly in the Pad dialog if required.

  • Rule - select to have the solder mask expansion for the pad follow the defined value in the applicable Solder Mask Expansion design rule.
  • Manual - select to override the applicable design rule and specify the solder mask expansion value for the pad. 
    • Top - enter the top layer solder mask expansion value. The value can be entered in either metric or imperial; include the units when entering a value whose units are not the current default. Default units (metric or imperial) are determined by the Units setting in the Other region of the Inspector panel in Board mode (accessed when no objects are selected in the design space), and are used if the unit is not specified. This field is accessible only if Tented is not enabled.
      • Tented - enable if it desired for any solder mask settings in the solder mask expansion design rules to be overridden, which results in no opening in the solder mask on the top layer of this pad and is therefore tented. When disabled, the pad is affected by a solder mask expansion rule or specific expansion value.
    • Bottom - enter the bottom layer solder mask expansion value. The value can be entered in either metric or imperial; include the units when entering a value whose units are not the current default. Default units (metric or imperial) are determined by the Units setting in the Other region of the Inspector panel in Board mode (accessed when no objects are selected in the design space) and are used if the unit is not specified.
      • Tented - check if it desired for any solder mask settings in the solder mask expansion design rules to be overridden, which results in no opening in the solder mask on the bottom layer of this pad and is therefore tented. When disabled, the pad is affected by a solder mask expansion rule or specific expansion value.
      • From Hole Edge - when enabled, the Solder Mask opening will follow the shape of the pad. The mask is, therefore, independent of pad shape and size and is scaled from both the hole size and shape. For example, a pad with a square hole will create a square mask opening that matches the hole dimensions, as well as the assigned expansion value. Also, note that a pad's expansion mask opening size will track any changes in the hole size.
If your component needs paste or soldermask shapes that are different from the pad shape, you can place design objects, such as fills, regions, tracks, or arcs, directly onto the top solder or paste mask layer in the library editor to create the required shape.
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