authors Shen-Fu Hsiao, Ming-Yu Tsai and Chia-Sheng Wen by ...web.cecs.pdx.edu/.../Deepika_Dendi_ آ 

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Text of authors Shen-Fu Hsiao, Ming-Yu Tsai and Chia-Sheng Wen by ...web.cecs.pdx.edu/.../Deepika_Dendi_...

  • authors

    Shen-Fu Hsiao, Ming-Yu Tsai and Chia-Sheng Wen

    by

    Deepika Dendi

  •  Introduction

     Synthesis flow

     Basic PTL Physical cells

     One-level PTL Logic cells

     Multilevel PTL cells

     Improvements

     Hybrid PTL/CMOS Synthesis Results

     Conclusion

  •  PTL outperforms CMOS for XOR rich applications.

     CMOS have edge over PTL in circuits which are not XOR based.

     Modified synthesis flow having both CMOS and PTL cells can give better results.

  • One-level PTL Logic cells

  • 1. If input of mux is connected to Vdd ,replace NMOS by PMOS and remove inverter in MUX. This reduces area, power and improves speed performance. This Mux is called NPMUX.

  • 2. Another improvement is to use the inverted signal available in MUX for signal inversion instead of using inverter

  •  Layout models are created for basic PTL logic cells.

     These layout models are used in placement and routing step after synthesis.

     Cells are characterized to create synopsis models.

     The models have area cost, parasitic capacitance, dynamic leakage power, delay etc.

     This information Is used by synthesis and P&R tools to generate physical layout according to the design constraints.

  •  Table V compares area and delay of different pure PTL synthesis methods

     Table Vl compares area,delay and power of both area optimized(AO) and delay optimized(DO) results based on different types of cell libraries

    1.Pure CMOS 2.Pure PTL

    3. Hybrid CMOS/PTL

  •  The paper presented a hybrid methodology that can easily be embedded in cell based design flow.

     From the results using 90nm technology, it is found that PTL outperforms over CMOS in power and area. Whereas Hybrid CMOS/PTL gives better results in AO and DO