What are end cap cells in VLSI?

The end cap cell or boundary cell is placed at both the ends of each placement row to terminate the row. It has also been placed at the top and bottom row at the block level to make integration with other blocks. Some standard cell library has also corner end cap cells to place the corner of the block.

What is fiducial cells in VLSI?

Fiducial cells are points accepted as fixed bases of reference. Marks indicating the order in which each reading or sample reading was taken. These cells contain integers, times, dates or other values, called fiducials, that provide a unique reference for each row of data values in the spreadsheet.

Why are substrate tap and well tap used?

taps are traditionally used so that your VDD and GND are connected to subtrate and n-wells respectively. This is to help tie them to your VDD and GND levels so that they don’t drift too much (especially towards the middle of the chip) and cause latchup.

Why decap cells are used?

Decap cells are basically a charge storing device made of the capacitors and used to support the instant current requirement in the power delivery network. To support the power delivery network from such sudden power requirements, decap cells are inserted throughout the design.

What are tap cells?

Well tap cells (or Tap cells) are used to prevent the latch-up issue in the CMOS design. Well tap cells connect the nwell to VDD and p-substrate to VSS in order to prevent the latch-up issue.

What is Halo in VLSI?

HALO ( Keep-Out Region): HALO is the region around the boundary of fixed macro in the design in which no other macro or std cells can be placed. Halo allows placement of buffers and inverters in its area. Halos of two adjacent macros can be overlap.

What are preplaced cells?

Some of the important or critical cell’s locations has to be pre-defined before actual placement and routing stages. and also few other cells such as RAM’s, ROM,s etc. Since, these cells are placed in to core before placement and routing stage, they are called ‘preplaced cells’.

What are well taps?

Well taps are traditionally used so that your VDD and GND are connected to subtrate and n-wells respectively. This is to help tie them to your VDD and GND levels so that they don’t drift too much (especially towards the middle of the chip) and cause latchup.

How DeCAP cells reduce IR drop?

Most commonly used methodology to resolve peak transient IR drop is to add the decoupling capacitance (Decap) cells in to layout. These Decap cells acts as local charge reservoirs and reduce the effect of peak IR drop on neighbouring circuits.

What are macros in VLSI?

Macro Cells are the Memory cells. These IPs have been designed by some other Analog design team, which can be used in the floor plan stage of the design.