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  1. #1
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    Wrong output in HSpice

    Hi
    I am new to HSpice and simulating a simple CMOS inverter, the netlist is as follows,
    Code:
    Inverter Circuit
    
    M1 OUT IN VDD VDD CMOSP L=0.18u W=1.8u
    M2 OUT IN 0 0 CMOSN L=0.18U W=0.9U
    VDD VDD 0 1.8
    VIN IN 0 0 PULSE 0 1.8 2n .5n .5n 7n 20n
    CLOAD OUT 0 20fF
    
    .OPTIONS LIST NODE POST
    .TRAN 200p 20n
    .PRINT TRAN V(IN) V(OUT)
    .LIB "tsmc_018um_model" CMOS_MODELS     
    .END
    when I simulate it using HSPICE J-2014.09-SP2 all is well, output is coming as expected in CosmosScope
    Click image for larger version. 

Name:	J2014cosmosScope.png 
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    also in avanwaves output is coming as expected,
    Click image for larger version. 

Name:	J2014avanwaves.png 
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ID:	158597

    but in my another lab where HSPICE L-2016.06-SP1 is installed, simulating the same netlist with HSPICE L-2016.06-SP1 output on cosmosScope is comming like this,
    Click image for larger version. 

Name:	L2016cosmosScope.png 
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ID:	158598

    even on changing the x-axis to (0 to 20n) the output is,
    Click image for larger version. 

Name:	L2016cosmosScope1.png 
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ID:	158599

    on avanwaves when i try to open the .tr0 file it gives error,
    Click image for larger version. 

Name:	L2016avanwaves.png 
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ID:	158601

    I am unable to figure out what is happening,
    please help me
    thanks in advance

    - - - Updated - - -

    Actually I have to work in HSPICE L-2016 so please help me getting the correct output.
    thanks

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  2. #2
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    Re: Wrong output in HSpice

    Maybe the problem is "another lab" and not the software
    version. Inspect the log file for warnings about missing
    .LIB target. Inspect the target model files to be sure they
    are where and what you think they are.



  3. #3
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    Re: Wrong output in HSpice

    Yes sir I have ensured that the LIB file is OK, actually yesterday night I simulated with HSPICE L-2016 in my first lab, actually both labs has HSPICE L-2016 but still no luck the same wrong output. Then I simulated on three different computers with same netlist and model files but HSPICE J-2014 gives correct output and HSPICE L-2016 wrong output. And no body in the lab including the instructors is able to fix the problem.

    please help me
    thanks



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    Re: Wrong output in HSpice

    Looking at your 3rd scope image... Its scale markings do not look the same as the other scope scales. Its time frame appears to be seconds, not nanoSec.

    As something to try...
    Rather than import the old netlist drawn in the old version...
    Draw the same circuit new in the version of software you say you must work in. Its netlist possibly has some subtle differences.

    Simplify it as much as you can. It may help if you start with a more basic circuit, and get the timeframe correct, and the tilmestep correct, and the scope scale correct. Etc.
    Then add components.

    Every simulator has its quirks. Software developers seem to avoid making their program easy to use. (Notice that your instructors cannot find the problem?) Of course software writers need to compete and add features that users demand. One has to be a longtime user to get to know the quirks.



  5. #5
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    Re: Wrong output in HSpice

    no luck please help



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  6. #6
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    Re: Wrong output in HSpice

    CLOAD OUT 0 20fF
    Is the load a capacitor by itself? That can give a simulator trouble.

    Try changing the load to a resistor. Compare the simulator results. See if the problem goes away.

    Then change the load to series RC. Compare all simulator results.



  7. #7
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    Re: Wrong output in HSpice

    Great thanks for your reply, now I am trying the simplest, voltage divider
    Code:
    *** TOP LEVEL CELL: R_divider{sch}
    R0 vout vin 10k
    R1 0 vout 10k
    
    * Spice Code nodes in cell cell 'R_divider{sch}'
    v1 vin 0 sin(0 5 1k)
    .OPTIONS LIST NODE POST
    .tran 1u 5m
    .print tran v(vout) v(vin)
    .END
    output of hspice l.2016, on cosmosscope
    Click image for larger version. 

Name:	cosmos1.png 
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ID:	159587

    after scaling the x-axis,
    Click image for larger version. 

Name:	cosmos2.png 
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ID:	159588

    awaves display,
    Click image for larger version. 

Name:	awaves.png 
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ID:	159589

    these above are ALL WRONG OUTPUTS.

    output of hspice j2014, on cosmosscope
    Click image for larger version. 

Name:	cosmos3.png 
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ID:	159590

    awaves display,
    Click image for larger version. 

Name:	awaves2.png 
Views:	3 
Size:	26.7 KB 
ID:	159591
    these above are ALL CORRECT OUTPUTS.

    I can't figure out where is the problem please help me.



  8. #8
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    Re: Wrong output in HSpice

    For further assistance it may require someone familiar with your setup and your simulator. Example, 'Unknown file error' may have to do with the way HSpice is installed on your computer, rather than your circuit or component models. Or the way one version of HSpice handles files, compared to another version.

    Nowadays simulators have become many and various. Each has its quirks no matter which simulator you use. You need to try this and that in order to cope with the unexpected.

    Those sloping plots imply that the component models are more complex than they need to be for building a 'simple cmos inverter'. Did you try using a single transistor to invert a signal (common emitter mode)? That works too. Did you achieve successful plots in all your labs?



  9. #9
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    Re: Wrong output in HSpice

    Till now I have tried 10 examples, the last is the above voltage divider, it has no transistor or any other device model involved. All examples are showing the same behaviour, they are running well with hspice j2014 but not with hspice l.2016.
    It is very strange and embarrassing situation.



  10. #10
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    Re: Wrong output in HSpice

    Although I lack hands-on experience with HSpice, I get the idea that software developers like to change things around from one version to the next. Perhaps it's their way of gaining continued revenue from their customer base.

    Did you subscribe to receive patches and updates?

    Did you locate a message board for HSpice?
    Did anyone present a similar problem as yours?



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  11. #11
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    Re: Wrong output in HSpice

    Not subscribe to receive patches and updates?
    I could not locate a message board for HSpice, is there any way or forum, email etc to ask this problem directly to the synopsys hspice team? I could not register to the synopsys community because Non-customer community registrations have been temporarily paused.

    All the students, teachers and users of HSPICE L2016 I met till now in my friend circle report the same problem, all are saying that HSPICE L2016 has some bug and produces corrupt simulation output files, and the left it and lost the hope completely.

    Please tell me how to ask to synopsys hspice personals about this problem, it is my last hope.



  12. #12
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    Re: Wrong output in HSpice

    It is very strange and embarrassing situation.
    Embarrassing for someone but remember you are not the one responsible.

    About computer programs there's a saying: 'If it's difficult to use it's not the user's fault, it's the programmer's fault.'

    they are running well with hspice j2014 but not with hspice l.2016.
    I have to work in HSPICE L-2016
    no body in the lab including the instructors is able to fix the problem.
    It's hard to believe these statements must co-exist. Someone who's just learning should not have to run up against this. What simulator did others in your circle turn to? After trying a few simulators (free, online, interactive, non-interactive), you should gain a perspective to make comparisons and contrasts.

    And, did you test various circuits with real hardware, and real oscilloscope?



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