VA A Gnd PULSE (0 vdd 2ns 100ps 100ps 5ns 10ns)
.
.
.
.measure tran delay_ar TRIG v(A) val='Supply*0.5' td=1ns rise=3
+ TARG v(out) val='Supply*0.5' fall=3
What's wrong?
the correct syntax for measuring delay in HSPICE is:
.measure tran delay_SUM_fall trig v(A) val=2.5 fall=2 targ v(SUM) val=2.5 fall=2
i think instead of writing this "val='Supply*0.5' " you have to specify the exact value. As i mentioned in the example here i am taking a supply of 5V and i am calculating the fall time of SUM output so i take 2.5V (50% of the input voltage) when it is rising
.MEASURE PROP-DELAY1 TRIG V(X0) TD=50ps VAL=0.9 RISE=1 TARG V(P0) TD=50ps VAL=0.9 Fall=1
with supply voltage of 1.8, 50% of rise and 50%of fall. With the above .measure and Prop delay we will measure propagation delay using Hspice.
thank you!
I wrote exact value then results changed a little! But there is same problem: for some of inputs there is negative TPHL or TPLH,because triger is after target.
There is this message for rise/fall time of outputs too:
.MEASURE tr_out never reached the trigger value, Measurement failed!
.MEASURE tr_out never reached the target value, Measurement failed!
meanwhile, I am working on Cnfets.
Hi Maryam Sharifi
when you have a high propagation delay then trigger time will be after the target time, which is the result negative value.
To solve this problem:
1- use a higher period or lower frequency to avoid that.
2- or you have an error in your design.
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