PSpice Hack Chat with Cadence

Join the PSpice R&D team for a special Q&A on circuit simulation.

Friday, March 30, 2018 08:00 am PDT Local time zone:
Hack Chat
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Join this Hack Chat by clicking on the JOIN HACK CHAT button. 


Alok Tripathi and Abha Jain will be hosting the Hack chat.

This Hack Chat is at 11a EST/ 8a PST/ 8:30p IST on Friday, March 30th. Please note new time for this chat!

Time Zones got you down? Here's a handy count down timer!

PSpice® is a tool used for circuit analysis. It allows the user to simulate a circuit and observe voltages and currents. Information is entered via a typed 'Net List' or by designing a visual schematic.

PSpice combines native analog, mixed-signal, and analysis engines to deliver a complete circuit simulation and verification. Whether you’re prototyping simple circuits or designing complex systems, PSpice technology provides high-performance circuit simulation to analyze circuits before committing to layout and fabrication.

Abha Jain has worked in Cadence Design Systems for 19 years, and has been a part of PSpice R&D for the last 10 years. She is an MTech in VLSI Design Tools and Technology, and holds multiple EDA patents.

Alok graduated in 1993, with a B. Tech. in Electrical Engineering. He started working at Department of Atomic Energy in 1993 as a power supply and control system designer for particle accelerators. Here he started using several analog design and simulation tools like PSpice for his designs and analysis works. Currently he is working with Cadence Design Systems and he is Product Engineering Architect for PSpice and OrCAD. He enjoys sharing his experience with PSpice and SPICE simulation with designers and loves to learn from them. 

In this chat, we'll discuss:

  • Challenges with System level simulation
  • Improving reliability, yield, productivity of your circuit design
  • Issues with Spice simulation and Magnetic Modeling

  • PSpice Hack Chat with Cadence transcript

    Sophi Kravitz03/30/2018 at 16:11 0 comments

    Sandeep roy says:9:24 AM
    hello people

    Sandeep roy says:9:24 AM
    anyone have any idea to create a .inc file

    Sandeep roy says:9:29 AM
    i need it to create a default bom template

    ðeshipu says:9:30 AM
    what does it have to contain?

    Sandeep roy says:9:31 AM
    suppose to change a default temperature for all sim profile :

    Sandeep roy says:9:31 AM

    Sandeep roy says:9:31 AM
    we have to provide this in .inc file

    Sandeep roy says:9:32 AM
    what header and footer it should have

    ðeshipu says:9:32 AM
    can't you just write that in a text editor?

    Sandeep roy says:9:34 AM
    yes i can write and save as .inc but when i include in sim. settings and simulate it gives me error

    Sandeep roy says:9:35 AM
    so, i was curious that what is the excat format to write a include file. any header or footer

    Sandeep roy says:9:35 AM
    i am not getting any relevant results from google search

    ðeshipu says:9:38 AM
    well, it would very much depend on the program you are trying to use it with, since we have no idea what that is, it's hard to help you

    ðeshipu says:9:38 AM
    I would check the documentation of that "sim" thing, whatever that is

    Sandeep roy says:9:39 AM
    sim= simulation

    WooDWorkeR says:9:39 AM
    circuit simulation? resturant simulation? rollercoaster simulation?

    Sandeep roy says:9:40 AM
    circuit simulation in PSpice

    WooDWorkeR says:9:42 AM
    .INC is a statement in PSpice

    Sandeep roy says:9:43 AM
    its a file to be included in Capture or Pspice to change Default settings

    WooDWorkeR says:9:45 AM
    to change the tempaerature you neet to set it via .OPTIONS

    WooDWorkeR says:9:45 AM



    General Formats : .OPTIONS |option name ...| or .OPTIONS (|option name|=|value| ...) The .OPTIONS command is used to set all options, limits, and control parameters for the various analyses. There are two types of options : flags and value options. The flag options can just be listed, the value options need a specific value to be assigned to it.

    Read this on Stuffle >

    Abha Jain says:9:48 AM
    .INC does not require a header or footer - could you share your out file?

    Abha Jain says:9:49 AM
    e.g. the following 1-line INC file will work: .OPTIONS VNTOL=1u

    Abha Jain says:9:50 AM
    are you writing TNOM=35? it needs to be .options TNOM=35

    Sandeep roy says:9:50 AM
    yes true i tried it before,,, in notepad i wrote .options TNOM=35 and saved is a .inc file and included in edit simulation window config tab to include a include file but got simulation error that the model was not found... but all models are from my inbuilt library

    Abha Jain says:9:51 AM
    Did you set up the library file from configuration files (edit simulation settings)?

    Abha Jain says:9:52 AM
    Looks like PSpice could not find the model definition, not a INC file issue.

    Sandeep roy says:9:52 AM
    yes i checked all.. once i remove the inc file i get my simulation result

    Ronak Shah says:9:52 AM

    PSpice vs Free.pdf
    364 KB

    Download File

    Ronak Shah says:9:52 AM
    PSpice: In regards to my question of why I would choose PSPice vs any free simulator available in the market, I found this good document explaining the difference. Well explained!

    Sandeep roy says:9:53 AM
    let me give you guys the error message

    Abha Jain says:9:54 AM
    yes. that would help

    K I R A has joined this room.9:54 AM

    WooDWorkeR says:9:54 AM
    nobody asked why you would use pspice

    Sandeep roy says:10:00 AM
    ronak thanks for the file

    Ronak Shah says:10:01 AM
    Well I did yesterday, I got a good document so I shared it

    Sandeep roy says:10:01 AM
    it will really help

    Sandeep roy says:10:01 AM
    as an...

    Read more »

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Kevin wrote 03/30/2018 at 16:12 point

I wonder if/when KiCad will be as a schematic tool so we don't have to say we use it by having it under Other.

  Are you sure? yes | no

Ronak Shah wrote 03/30/2018 at 15:53 point

How do I import models for components in my circuit right from the web?

  Are you sure? yes | no

Ted Yapo wrote 03/30/2018 at 15:39 point
What about monte carlo simulations, for example to test performance over component tolerances?

  Are you sure? yes | no

Alok wrote 03/30/2018 at 15:42 point

Yes. You can perfrom MC analysis. It is so easy to do in PSpice. You simply define glocal or local tolerances and hit run. You can pick any output node after analysis is run and find out the effect. No need to run again for checking diferent nodes. 

PSpice Advance Analysis further offers you superior capabilities over and above what is offered by regular Spice simulators.

  Are you sure? yes | no

Ronak Shah wrote 03/30/2018 at 15:36 point

How do I avoid convergence errors in PSpice?

  Are you sure? yes | no

Alok wrote 03/30/2018 at 15:38 point

SPICE simulators relies on iterative solutions methods such as Newton Raphson to solve nonlinear circuit equations. When these iterative methods are not able obtain a stable solution they report these are convergence error. PSpice offer Auto Convergence mode, in this mode PSpice tries to achieve convergence or solution by intelligently tweaking simulator options.  You can also refer “Convergence and “time step too small errors” topic in PSpice user guide to know more about handling convergence problems.

  Are you sure? yes | no

Sophi Kravitz wrote 03/30/2018 at 15:35 point

what are some of the obscure characteristics of chips that PSpice can model?

  Are you sure? yes | no

Alok wrote 03/30/2018 at 15:39 point

You can model a devices like resolver or Pulse oxymeters. One can also model a ferrite core - a highly non linear device with hysteresis and saturation effets.  

  Are you sure? yes | no

Ronak Shah wrote 03/30/2018 at 15:31 point

How do I increase productivity and reduce cost at the same time for my circuit? What tools does PSpice have?

  Are you sure? yes | no

Sophi Kravitz wrote 03/30/2018 at 15:33 point

this is a technical chat, so we only discuss the technical aspects of the tool here

  Are you sure? yes | no

Ronak Shah wrote 03/30/2018 at 15:34 point

OK. Thanks! 

  Are you sure? yes | no

Prof. Fartsparkle wrote 03/30/2018 at 15:27 point

Is spice simulation used in circuits that is almost exclusives digital and if so how do you model a simulation like that if most modern ICs are black boxes?

  Are you sure? yes | no

Alok wrote 03/30/2018 at 15:37 point

No Spice simulation not for digital. You can simulate almost anything. It is mostly used for Analog. You can model/simulate black box - if you know Transfer function or input out characteristics. take the example of switching or PWM controller - No manufacture publishes actual implementation - they just provide functional block and people do model and simulate such IC using datasheet only, no internal details like circuit diagram. PSpice support ABM and C language as modeling language - which enables you to model a black box device based on input/output characteristics.

  Are you sure? yes | no

Ronak Shah wrote 03/30/2018 at 15:26 point

MATLAB- PSpice? What's the integration about?

  Are you sure? yes | no

Abha Jain wrote 03/30/2018 at 15:52 point

MATLAB-PSpice interface - also called SLPS - allows PSpice models to be simulated from inside a Simulink model.

So you could start with an algorithmic model in SLPS, then move some of the blocks to transistor-level implementation in PSpice, and simulate the entire system together.

  Are you sure? yes | no

Ronak Shah wrote 03/30/2018 at 15:17 point

@Sophi Kravitz Does PSpice have any motor and/or electromechanical models?

  Are you sure? yes | no

Taylor Street wrote 03/30/2018 at 15:15 point

I have a part I want to simulate in a circuit. But I can't find a SPICE model for it. Can I make my own?

  Are you sure? yes | no

Alok wrote 03/30/2018 at 15:36 point

Yes. You can. You can not only model several devices using PSpice Modeling apps or PSpice Model Editor. These tools lets your create a models for varity of devices

  Are you sure? yes | no

Manish Agarwal wrote 03/30/2018 at 15:13 point

Can I save the probe display with some settings, and restore it in next session?

  Are you sure? yes | no

Abha Jain wrote 03/30/2018 at 15:54 point

Yes - In PSpice probe, you can create any combinations of plot windows, and save the display with a name of your choice. You can load it from the Display Control menu later - it is saved in a prb file at the same location as the dat file.

It can also be used to save measurements

e.g. Create a measurement - bandwidth of a trace . save it as a display. In the next run, PSpice will load the dat file, and automatically evaluate and show the saved measurements.

  Are you sure? yes | no

karnane wrote 03/30/2018 at 14:37 point

Does PSpice have any motor and/or electromechanical models

  Are you sure? yes | no

Alok wrote 03/30/2018 at 15:37 point

Yes. PSpice comes with set of DC motor models and models for several other electromechanical components like Relay, Tacho, flywheel, gearbox, viscosity etc. In addition, you can also co-simulate any MATLAB automotive models with PSpice

  Are you sure? yes | no

Ronak Shah wrote 03/29/2018 at 22:24 point

There are a lot of free simulators in the market, what are the three main reasons I would prefer PSpice over them?

  Are you sure? yes | no

K.C. Lee wrote 03/29/2018 at 22:45 point

Each of the spice implementation might have tweaks to enable the solver to improve  convergence.

The other reason would be that it is a well known package so some vendors might be more willing to supply a more accurate spice models in encrypted form.  e.g. don't expect TI to give encrypted model for (LinearTech) LTSpice.

  Are you sure? yes | no

Ronak Shah wrote 03/30/2018 at 14:28 point

Does PSpice have a better solution to solve non-linear circuits to avoid convergence errors?

Yes, and I see that there are various PSpice models from most IC vendors, thanks for that!

  Are you sure? yes | no

K.C. Lee wrote 04/01/2018 at 21:55 point

>Depending on the vendor, Spice works pretty hard to make even poorly constructed models converge. Most modern Spice simulators employ variations of the described operating-point convergence methods and have fine-tuned the algorithms.

That's essential what I have said.  Without knowing the inner working or working with Pspice vs other spice, I can't say if theirs are better or not.

If doing the tweaks requires someone working with the right experiences on them full time for months, then chances are a paid package would have the resources that a "free" package won't have.  "Free" isn't free anymore if you have to be the one fixing the code.

  Are you sure? yes | no

Sophi Kravitz wrote 03/28/2018 at 12:44 point

Please note different time for this chat! This Hack Chat is at 11a EDT/ 8a PDT/ 9:30p IST on Friday, March 30th

  Are you sure? yes | no

Alok wrote 03/30/2018 at 14:36 point

I think timing are 8 AM PST/11AM EST /8:30PM IST.

  Are you sure? yes | no

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