Cadence icfb – Tips and Tricks

Cadence comes with a variety of tools. A few among them are listed here…

  • Virtuoso Schematic for schematic capture.
  • Analog Artist (Spectre) for simulation.
  • Virtuoso layout for layout
  • Diva for Postlayout verification

Each of these tools are invoked by the typing respective command in the command terminal. The tools and the respective commands are :

Command description For invoking the tools
layout Layout only (and DRC).
spectre Spectre RF Circuit Simulator(like spice)
msfb Layout, schematic capture, VHDL, and Simulation tools
icca Place and Route tools.
icde Schematic capture only (and netlisting).
icds Schematic capture and VHDL.
icms Schematic capture, VHDL, Simulation, & Analog Artist/td>
icfb Everything…

The Cadence command “icfb” makes all the licensed tools available, and you can check out licenses from the OptionsLicenses… menu. However, you can help reduce unnecessary license usage by running only the tools you need.

Tips :

  • Avoid using mv, cp, etc… linux commands for moving cadence design files. Instead use the option available with Library Manager
  • Always prefer to have Library Manager window open.
  • The cds.lib file follows the following format:

    DEFINE (name by which the library is presented) (Path to the directory containing the “techfile.cds” of the library)

    For example, to add the Microwave library, append the following line in cds.lib:
    DEFINE MicrowaveLibrary $CDS_INST_DIR/tools/dfll/etc/cdslib/artist/microwave


Hotkey Description Schematic Func Layout Func
i instance add an instance to the cell -do-
k ruler measure distance between two points
shift k delete ruler delete all the earlier placed rulers
f fit to screen fit the entire layout to screen
l label label a net -do-Make sure that you have selected text layer in LSW window. Otherwise it create DRC errors.
shift c chop/cuts pieces of selected item Select the interconnect to chop and place the cursor at the starting point. Press shit+c. Then select area to chop
shift m merges selected items
ctrl r redraw
ctrl p insert pin
q query Gets info on the currently selected instance. helpful for changing the properties of instances -do-
F3 Pressing F3, after a hotkey(say r) pops up a window, which details about the options available with that hotkey. -do-
Esc cancels current mode -do- -do-
z zoom zoom-in selected area; select area with mouse left click
ctrl z zoom in zoom in by 2X
shift z zoom out zoom out by 2X
ctrl f layers selection hide all layers
shift f layers selection display all layers
ctrl p pin create a pin


LSW – Layer Select Window

This window tells about all the layers (metal, poly, n-plus etc)that are available in the process. This window pops up when layout is invoked. Following are the options available on this window for selection of layers and instances.

Option Acronym Description
AV All View you see all the layers
NV No View You see *only* the selected layer. You may have to hit ctrl-r (redraw) to see the new view. You can select more than one layer to view.
AS All Select When you select, you select every layer.
NS No Select When you select, it’s everything *but* that layer.
inst instance Deselect this to only select the current hierarchy, but no blocks. Great way for deleting lots of wire traces without deleting the actual transistors you’ve placed.
pin pin deselect this and you can’t select the pins. BE VERY CAREFUL WITH THIS ONE. I’ve left it deselected many times and when I’ve gone to move chunks of layout, the pins stay behind, causing major LVS headaches later.

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