LEF of a cell contains?

[sun_ray]

What informations a LEF of a cell will contain? What is RECT in the LEF of a cell?

 

[biju4u90]

lef of a cell?? Do you mean the lef file? The technology lef file and library lef files?

 

[sun_ray]

library lef files containing lef of cells like NAND, NOR, adder etc.

 

[biju4u90]

The technology lef file describes the design rules of the particular technology. The library lef file specifies how the different standard cells in the library are fabricated in accordance with the design rules. This explains the geometry of the different cells specified. RECT is used for defining the geometry of the pins in the cells which represents a rectangle formed by the specified metal layer.

 

[Anand Cool B]

The LEf files contain the layout data.The data of what all layers you have used in the layout.The Rect signifies the quadrant or axis data with respect to the 0 axis.Instead of drawing the layout in the layout edit terminal you can edit in the lef file using rect command and respective axis to edit in the layout view.

 

[sun_ray]

The technology lef file describes the design rules of the particular technology. The library lef file specifies how the different standard cells in the library are fabricated in accordance with the design rules. This explains the geometry of the different cells specified. RECT is used for defining the geometry of the pins in the cells which represents a rectangle formed by the specified metal layer.

Does the library LEF also describe the metal layers of the cell? does it also describe the different metal layers and their positions in the cell? Does it also describe nmos and pmos area of the cell?

What is the typical file name extension of a technology lef? is it .tf or .lef? Will not there be a common technology lef file for all the cells in a library lef file corresponding to a technology?

What does RECT 0.23 0.33 0.29 0.44 means?

 

[Anand Cool B]

Does the library LEF also describe the metal layers of the cell? does it also describe the different metal layers and their positions in the cell? Does it also describe nmos and pmos area of the cell?

What is the typical file name extension of a technology lef? is it .tf or .lef? Will not there be a common technology lef file for all the cells in a library lef file corresponding to a technology?

What does RECT 0.23 0.33 0.29 0.44 means?

Usually all the layers like metal 1 metal2 pMOS(orPfet) OD etc etc drawn and its rectangular sizes data with respect to 0 axis wil be present.The RECT (x0 x1 y0 y1) is the format.

 

[biju4u90]

@sun_ray: No. The library lef file gives the information about the cell pins and the total cell area. It wont give you the idea about the metal routing, functionality of the cell or transistor informations inside it. The library lef cells are black boxes with connectivity information which is the pin information. With this pin information and cell dimensions, the PnR engineer or tool can place the cells in the design. Both the technology lef file and library lef file can be of .lef format. Like Anand told, RECT 0.23 0.33 0.29 0.44 represents the metal layer positioning for the pin.