Hello everyone, This is hopefully an easy question. Now that I started working on the IBIS buffers for the VHDL-A(MS) version of the library, I ran across this question. I think my work on the PWL sources made me aware of it... What should be the threshold level(s) on the input stimulus (and perhaps the enable also) to the buffer? In the current Verilog-A implementation I implemented a single value Vth parameter with a default of 0.5V, however, I just remembered that a very popular tool we all know does the following: At t=0 for transient analysis (or for DC analysis), the buffer goes to HIGH state if V_in > 0.5 and to LOW in the opposite case. Next, if the buffer is in HIGH state, it will go to LOW state if V_in < 0.2. If the buffer is in LOW state, it goes to HIGH state if V_in > 0.8. Another one of our very popular tools does it differently, they go to the high state immediately when the input value goes above 0V, and go to the low state immediately when the input goes below 1V. 1) Considering that in the event triggered PWL sources I implemented two threshold parameters, Vth_R and Vth_F for the rising and falling edge stimulus, the least I think I should do is have two threshold parameters for the buffer models also. On the other hand, as far as I know, these favorite tools of ours do not give an option to the user to change these thresholds (but I could be wrong on that one). If true, wouldn't it be better if the library would also hard code the threshold parameter? 2) If the answer is hard code them, what should be the value for Vth_R and Vth_F? If the answer is don't hard code them, what should be the default value for them? Thanks, Arpad ======================================================== --------------------------------------------------------------------- IBIS Macro website: http://www.sisoft.com/ibis-macro IBIS Macro archives: //www.freelists.org/archives/ibis-macro To unsubscribe send an email: To: ibis-macro-request@xxxxxxxxxxxxx Subject: unsubscribe