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What are tiehi and tielo cells?

NAADHAN

Hi all,

Please can any one explain me what are 'tiehi' and 'tielo' cells ? and how are they used in designing ?

 

 

Thanks & Regards,

NAADHAN

Parents

  • Not all designs use tie cells. I have found this to be a customer preference, although apparently there are benefits to using them, such as some ESD protection.

    In a design without tie cells, unused inputs are tied to logic-high or logic-low, and these connections are made by routing the input pin right to the pwr/gnd grid. 

    In a design with tie cells, unused inputs in the original netlist are tied to logic-high or logic-low, and somewhere during the physical design process, tie cells are inserted. The unused inputs are then connected to a tiehi or tielo cell.

    Adding tie cells in Encounter is very easy:

     addTieHiLo -cell "TIEHI TIELO"

    There are other options to the addTieHiLo command, as well as the setTiHiLoMode command, so please check the docs for your specific needs.

Reply

  • Not all designs use tie cells. I have found this to be a customer preference, although apparently there are benefits to using them, such as some ESD protection.

    In a design without tie cells, unused inputs are tied to logic-high or logic-low, and these connections are made by routing the input pin right to the pwr/gnd grid. 

    In a design with tie cells, unused inputs in the original netlist are tied to logic-high or logic-low, and somewhere during the physical design process, tie cells are inserted. The unused inputs are then connected to a tiehi or tielo cell.

    Adding tie cells in Encounter is very easy:

     addTieHiLo -cell "TIEHI TIELO"

    There are other options to the addTieHiLo command, as well as the setTiHiLoMode command, so please check the docs for your specific needs.

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