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multiple cells - single layout

HansRey

Hi,
I have 3 cells with each their own lib-model. Since the layout of the combination of these 3 cells is very critical, I would like to use a single layout for the combination of these cells.

So in my netlist I would have something like this:


CELL1 u_cell1 ( Y, A, B)

CELL2 u_cell2 (X, C, D)

CELL3 u_cell3 (Z, E, F)

But In layout I would like to use a single cell CELL123(X, Y, Z, A, B, C, D, E, F). Making a single lib-file for this cell is not feasable due to the timing dependencies between A, ..., F

Anyone got any advice on how to handle this?

Kind regards!

  • Can you please elaborate "due to the timing dependencies between A, ..., F" . I am not able to get which timing dependencies will the .lib miss.

  • The main problem originates from the fact that I want to use a flipflop and a latch in a single cell. This construct is not allowed in RTL Compiler (except for scan flipflops or register banks).

    Also, characterizing a cell with fliplfop+latch takes a lot more time than just characterizing each cell seperately. The number of possible inputs increases exponentially when I combine the 2 cells in a single cell.

    Another reason why I would use multiple cells in stead of a single cell is the complexity of a single cell: I have a lot of signals which are creating pulses / are timing dependant on some inputs, which means the function can not easily be defined in a single cell...

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