nige
Newbie level 5
hi, everybody, I'm doing a post-layout simulation using the lpe hspice netlist and two troubles puzzled me now. I hope somebody can help me.
*the first puzzle: as we all know, the foundry usually has a limition of "w" value about the mosfet, so when we design a big mosfet, we used a legal "w" value and argument "M". but I found in the lpe hspice netlist, all the big mosfet directly have a width value of "w times M" instead of "w" and "M".
for example:
pre layout nelist: M1 2 3 4 vss model L=0.24u W=80u M=9
post layout netlist: M1 2 3 4 vss model L=0.24u W=720u
can the second type of netlist be simulated post-layout directly?
*the second puzzle: the post-layout netlist must have some values of "AD","AS","PD" and "PS", so if we used the argument "M" at the same time, is the effect of "AD","AS","PD" and "PS" multipled ?
the two puzzle refer to almost the same question, I guess the netlist as
"M1 2 3 4 vss model L=0.24u W=720u"
can't be simulated directly, so we should change the netlist into the form of
"M1 2 3 4 vss model L=0.24u W=80u M=9" and we must add the parasitical value of "AD","AS","PD" and "PS" into it manually. In this conditiono,how about the the effect of "AD","AS","PD" and "PS"? I don't think the value of "AD","AS","PD" and "PS" can be divided by "M".
thank you in advance.
*the first puzzle: as we all know, the foundry usually has a limition of "w" value about the mosfet, so when we design a big mosfet, we used a legal "w" value and argument "M". but I found in the lpe hspice netlist, all the big mosfet directly have a width value of "w times M" instead of "w" and "M".
for example:
pre layout nelist: M1 2 3 4 vss model L=0.24u W=80u M=9
post layout netlist: M1 2 3 4 vss model L=0.24u W=720u
can the second type of netlist be simulated post-layout directly?
*the second puzzle: the post-layout netlist must have some values of "AD","AS","PD" and "PS", so if we used the argument "M" at the same time, is the effect of "AD","AS","PD" and "PS" multipled ?
the two puzzle refer to almost the same question, I guess the netlist as
"M1 2 3 4 vss model L=0.24u W=720u"
can't be simulated directly, so we should change the netlist into the form of
"M1 2 3 4 vss model L=0.24u W=80u M=9" and we must add the parasitical value of "AD","AS","PD" and "PS" into it manually. In this conditiono,how about the the effect of "AD","AS","PD" and "PS"? I don't think the value of "AD","AS","PD" and "PS" can be divided by "M".
thank you in advance.