Re: HSpice is better than Pspice (Orcad)
infomissing123 said:
Hspice gives more accurate results than Pspice (Orcad) does. I've used both for the same project and the difference was as much as 0.5V (DC output of an opamp that I designed). As far as netlist generation for hspice, do it by hand. It's surprisingly easy, especially if making digital circuits which have a lot of shared components.
i am agree with you about the benefits about hspice. but the only thing i want to describe here is how to generate the netlist, indeed, any tools can capture the circuits and generate netlists are candidates for this tasks. like orcad's capture (not pspice), woffice,composer, and even the Protel, the different is how ease to modify your parts specially for hspice.
like orcad's(now cadence) products orcadv9.1, which will contail the capture(input the circuit and as a front end to other tools) PSPICE, and a PCB layout tools. you can see those tools are three different and independed tools, and you can use any tools above independently if you give the input files correctly. but fortunately, orcad glue those tools, and you can those tools more easily. like simulating circuits in orcad using PSPICE. you will do this step:
1. input the circuit using some parts in pspice parts libray(using orcad's capture)
2. setup up some simulating profiles.
3. simulate this circuits using pspice and probe the results.
those are you seen. and do it by yourself. indeed. the software do some important steps automatically.
1.generating the netlists using the contact informating and parts PSPICE templates informations in schematics .
2.using the profiles to generate some special simulating command.
3.use the information above. generate the Cir which is input file of pspice.
4.run the pspice.
runing.....
5. back annotated the results, by read the output of pspice.
as we know hspice is a kind of spice. and use normal spice syntax, but it have some advanced functions different than other verions spices of other vendors.like PSPICE. in
1.special simulate commands.
2.some special parts like capacity varied with input voltage. ideal OP. and so on.
3. some commands usage is different from others like .lib and library files
with the snapshot above. we can learn that the orcad's capture can gererate .cir files for pspice. why not generate the .sp file for Hspice?
from manuals of orcad. we can learn that in the capture 's library for pspice,all parts have a template named PSPICE template to meet the special need for generating informats for spice. simplely like C which PSPICE templates is C_%refer% %1 %2 %value. ( i am not sure please refer the manuals)when captrue want to generate the netlist. it will replace the %refer% with the part number in scematic . %1 with the plus node. %2 with minor node. %value with the capcity. if in scematics a C with part name C11 and conected by node1,node2, with value 1pf. the capture will product this results:
C_C11 node1 nod2 1pf
which is suit for spice syntax. both for pspice and hspice. use this function you can generate some sepical parts for hspice. and even the simulateing command. like ideal OP and .tran ......
for instances. ideal OP in hspice have syntax like E_refer 1 2 3 4 OPAMP ( i am not sure) with _refer are part name. 1 2 3 4 will be the input and output node. the OPAMP will indicated it is a ideal OP. so in parts's templeat you will write like this E%refer% %1 %2 %3 %4 OPAMP then the capture will give you suitable result.
commands can be inputed in scematics too by using the PSPICE template. like .tran .noise .measure and so on. in my libaray for hspice i have a parts will give me opporunity to input command up to 10 sentences. it is suit for major tasts in my domain.
wise my introduce will help you. thanks
.
BTW, any other secematic input tools can do this task, like composer from candence. a skill ( a language from cadence) file is needed to generate the hspice netlist. it is hard to learn and to modify. so why i choose the orcad the reason is ease to learn.. to use.. . and to modify the parts...... thought i alway use the composer in workstation.
BTW again. it is said that the simulating result is different in window and in unix workstation even have the same input files and options, and some version of hspice. i am working in a SUN workstation. which will have signoff results.