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 power estimation using rc 

Last post Wed, Feb 29 2012 12:41 PM by RCsyn. 0 replies.
Started by RCsyn 29 Feb 2012 12:41 PM. Topic has 0 replies and 2549 views
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  • Wed, Feb 29 2012 12:41 PM

    • RCsyn
    • Not Ranked
    • Joined on Wed, Feb 29 2012
    • Posts 1
    • Points 5
    power estimation using rc Reply

    Hi all,

    I got a question about power estimation using cadence rc.

    I have two designs in HDL. Both of then have a 1-bit full adder. After synthsis, and post-simulation with the netlist with the same test data, I found the output toggle rate of these two 1-bit full adder are different, even though they have exactly the same input toggle rate. What could be the reason that the output toggle rate are different? Thanks~


    ============================
    1-bit full adder in Design 1 (tcf file):
    ============================
    instance("FA0_15") {
    pin() {
    "A" : "0.747505 390";
    "B" : "0.240519 372";
    "C" : "0.256487 384";
    "Cout" : "0.342315 454";
    "SUM" : "0.559880 478";
    }
    instance("g58") {
    pin() {
    "A" : "0.240519 372";
    "B" : "0.747505 390";
    "CI" : "0.256487 384";
    "S" : "0.559880 478";
    "CO" : "0.342315 454";
    "n2" : "0.183633 320";
    "n3" : "0.050898 98";
    "n4" : "0.185629 312";
    }
    }
    }

    ============================
    1-bit full adder in Design 2 (tcf file):
    ============================
    instance("FA0_15") {
    pin() {
    "A" : "0.747505 390";
    "B" : "0.240519 372";
    "C" : "0.256487 384";
    "Cout" : "0.342315 538";
    "SUM" : "0.559880 838";
    }
    instance("g62") {
    pin() {
    "A" : "0.240519 372";
    "B" : "0.747505 390";
    "CI" : "0.256487 384";
    "S" : "0.559880 838";
    "CO" : "0.342315 538";
    "n2" : "0.183633 382";
    "n3" : "0.050898 98";
    "n4" : "0.185629 390";
    }
    }

    ======================================

    both g58 and g62 are the instance of "FA1D0":

    FA1D0 g58(.A (B), .B (A), .CI (C), .CO (Cout), .S (SUM));
    FA1D0 g62(.A (B), .B (A), .CI (C), .CO (Cout), .S (SUM));

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    • Post Points: 5
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Started by RCsyn at 29 Feb 2012 12:41 PM. Topic has 0 replies.