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Simulating LT1990 on Circuit Maker 2K

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JRoque

New Member
Hello,

I've been trying to simulate Linear's LT1990 diff amp on my (t)rusty Circuit Maker 2000 program. I downloaded the SPICE model from the Linear website. I set it up on the circuit below but when I run the simulation, I get a series of similar errors, starting with:

*EICM 140 0 VALUE={(V(21)+V(22))/2}*
*
* Error in preceeding PARAM line: No match for parameter in: {(V(21)+V(22))/2}

I can simulate the same circuit with a different amp; one that came with the product.

It's been many moons since I've used CM2K or have done any simulation so I might be missing something obvious. I'd appreciate your help.

Thanks,
JR
 

Attachments

  • LT1990.GIF
    LT1990.GIF
    3 KB · Views: 254
The circuit you attached looks hooked up right externally. The LT1990 model parameters do line up with pin numbers of actual part. Is the one you attached the one that works or the one giving your errors?

For the circuit that gives you errors, attach the netlist (output file) showing all circuit connections. It is important to first make sure that the external connections are correctly lining up with the internal model connections. We'll go from there if you haven't figured it out by then.
 
The one attached is the one throwing the error. It's configured for a gain of 10, per datasheet.

I've attached the netlist here and will take a look at the pins on the circuit vs the model.

Thanks for your reply.

JR
 

Attachments

  • OpAmp_differential_test3A.Net.txt
    3.7 KB · Views: 170
JRoque said:
The one attached is the one throwing the error. It's configured for a gain of 10, per datasheet.

I've attached the netlist here and will take a look at the pins on the circuit vs the model.

Thanks for your reply.

JR

Well, at a glance it looks like it is not liking the VALUE = {..expression..}

In the circuit maker 2000 help file, look up the "E" element for example to check the usage of passing a VALUE expression. The above expressions are valid for PSPICE and work fine in both of my simulators.

So double check the usage. It might be as simple as changing the "{}" to "()"

See if that gets you somewhere.
 
You are correct. CM2K doesn't seem to like the squiggly brackets. I removed those and got past that error. I'm still working on it because, as you also pointed out, I believe I might have a mismatch between the device pins and the model input.

Much appreciate your help in getting me past the rough spot.

JR
 
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