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Does anyone know of a search engine like Mouser/Digikey where you can narrow down parts based on voltage/package type/etc., but exclude all results without PSpice models? Unless I'm doing it all wrong, the searching in OrCAD Capture basically assumes you already know what part you're looking for since there is no real sorting functionality other than by overall categories. Do any other spice implementations provide such functionality?

I've used PSpice during college for learning basic circuit design, and recently picked it back up thinking it could aid in a current design project. It seems to work great for basic circuit analysis, but for practical applications I've found myself jumping back and forth between the OrCAD model library, Mouser, DigiKey and several manufacturer websites trying to find a part that will meet my design requirements and still have a spice model available. After a few days of this, its seeming to be terribly time inefficient and might make more sense just to order parts and make prototypes. Is this just the nature of the beast or am I just missing something here?

My current workflow is something along these lines:

  1. Sketch circuit on paper
  2. Find parts that meet design criteria using Mouser/Digikey advanced search/sort
  3. See if I can find the part in the OrCAD Library or Manufacturer Website.
  4. If I find the part, great, but if not, then I go back to step 2 and select the next best part.

So far, I seem to be on an endless loop between steps 2 to 4 for even seemingly simple parts like voltage regulators.

The other possible workflow I tried but still seems terribly inefficient is:

  1. Sketch circuit on paper
  2. Search OrCAD Library for part of same category (e.g. positive voltage regulator) and just go down the list. Copy first part # on the list
  3. Copy first part number in the OrCAD list in the category of interest, and search Google/Mouser/Digikey for the datasheet. If the part meets my design requirements, then great, but if not, then I go back to step 2 and select the next part in the list.

This seems like an awful lot of trial and error. Can anyone point me to either a more efficient search engine as described in the first paragraph, or a guide/walkthrough for a more time efficient workflow using PSpice, or another Spice variant that doesn't result in such lost time on trail and error?

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  • \$\begingroup\$ I'm used to getting SPICE models from manufacturers directly. In addition, instead of actually using a spice model for, say, a voltage regulator, I would use a simple supply instead (maybe with a second supply to act as noise source?) during simulations. \$\endgroup\$ – Joren Vaes Oct 5 '18 at 14:54
  • \$\begingroup\$ Thanks for the comment Joren, and I agree that I can swap out more basic parts like a voltage source for a voltage regulator in some cases, but this would seem to have a few inherent issues: 1.) There's no way to model/check for problems inherent to the limitations of the voltage regulator (e.g. your supply voltage is too low resulting in unexpected levels at output). 2.) You can't design a PCB layout unless you at the very least make a custom PCB footprint for the unmodeled part. 3.) There aren't any real good substitutes for more advanced parts (battery protection circuit, etc.). \$\endgroup\$ – TopherBuckley Oct 5 '18 at 15:02
  • \$\begingroup\$ Also I should mention that I did try an additional workflow, where I'd start at a manufacturer website that provides a list of all parts with a spice model in their portfolio, but again I haven't see anything other than a basic list, i.e. no way to sort in a similar manner to Mouser/Digikey based on design parameters, so its again a trial and error exercise starting with the first part on the list and checking the datasheet, then back to the list. \$\endgroup\$ – TopherBuckley Oct 5 '18 at 15:05
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Unfortunately, most of the IC vendors would rather provide you with a model in their proprietary simulator format than in a generic format that would allow you to co-simulate their parts with their competitors' parts. TI provides models for Tina-TI, Linear and Analog provide models for LTSpice, etc.

Some vendors may provide models for Spice3 or PSpice, but rarely will they provide models for both.

Your options are

  1. Learn which vendors provide PSpice models and only use their parts.

  2. Learn enough Spice3, LTSpice, and PSpice syntax to be able to manually convert models from other formats to PSpice. This can be anything from trivial for simple models to very difficult for tricky ones.

  3. Use each vendor's proprietary simulator to model the subcircuit using their IC, and then use good systems engineering practices to combine subcircuits and design a working system. Then verify with testing on the physical circuit.

I strongly recommend you get comfortable with option 3. At some point your designs will become complex enough it won't be reasonable to simulate the complete system in Spice, so you'll need to understand how your subcircuits interact and be able to design this way at that point anyway.

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  • \$\begingroup\$ Part 1: @The Photon thanks for your answer. I was starting to conclude the same, but it seems the answer to the question of if such a search engine exists is simply "No." I appreciate your workflow tips and they do seem to be the best available, but I still have the same core issues with all of them. I have found several vendors that offer either PSpice or other spice models from some parts, but not all. Therefore I still run into the trail and error loop of looking for an appropriate part via an advanced vendor search engine (e.g. TI), only to find that I have to cycle through countless \$\endgroup\$ – TopherBuckley Oct 8 '18 at 3:05
  • \$\begingroup\$ Part 2: possible parts before finding one with a spice model. TI has nice search/sort features on their site, but I don't see any way to filter for "must have spice model" or similar. So again, I search/filter down until I have 10-20 parts that could work with my design, and click to open each until I find one with a spice model. This process gets even longer in cases where I exhaust the full list of perfectly compatible parts and then have to remove one filter (e.g. input voltage of 5V) in order to find a part that has a Spice model, then have to rework the design to account for a \$\endgroup\$ – TopherBuckley Oct 8 '18 at 3:06
  • \$\begingroup\$ Part 3: different input voltage. My core question is how to eliminate all that wasted time of trail and error finding a suitable part with a Spice model, but the other core question here is how do people use all of the vast array of parts that don't have Spice models? Is there nothing better than pencil and paper even in 2018? This just comes as a shock to me. \$\endgroup\$ – TopherBuckley Oct 8 '18 at 3:06

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