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Problem creating opamp with spice data

dexter23

Let me start by saying that i'm new to using simulation tools, so it's probably a rookie mistake, but.

 

In my design i have a LM385(DR) (dual) opamp and want to simulate the circuit.

I 'created' the schematic symbol, i downloaded the spice model from the Texas instruments website, i added it to the symbol (like in this video).

I ran in to problems,

1) The LM385 is a dual opamp so i made the symbol with two opamp parts and 1 power supply part

  I have not been able to get the power pins connected, keep getting error that the part has to few pins.... i can't get past this error and can't save the symbol with simulation data.

2) Created a new symbol with 2 opamp parts with the power pins in the same symbol (like in the video)

  That seemed to go a lot better, i entered the link to the simulation data, edited the pin mapping data and was able to save the symbol + sim data.

 

However when trying to run the simulation i got an error that (simulation) pin 3 (that is V+) was not connected, strange, i know i entered it.

Back to the sim edit, it showed that power pin 8 (= spice model pin 3) was not connected, so i changed it to pin 8, checked the other opamp and saved it.

Just for fun i re-opened the editor and checked it again, what do you know... pin 8 (should be model pin 3) was again not connected....

 

What am i doing wrong here (in symbol variant 1 and 2) ????

 

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  • 0

    From the images it looks like you have duplicate pins for 4 and 8.  Instead of placing duplicate pins in each sub part, if you want them to display on both parts, assign them to the special Part Zero.  This way there will only be one actual pin, but they can displayed on the individual parts.  Remove the duplicates from the other part and remap the pins, and the mapping should stick.

     

    The setting for which part a pin belongs to can be found in the Pin Properties, open this, and change the Part Number field to 0 if you want to use this special pin mode.

     

    Another alternative, which I see more commonly used, is to create a 3rd part of the package to hold the power pins.

     

    I hope that helps.

  • 0 in reply to csiemer

    Thank Colby,

     

    You solution works for my 'problem 2', but your alternative solution equals my 'problem 1'.

    For the simulation a made a second version of my opamp so that worked.

     

    But i would also like to know how to do it (right) with a separate part for the power pins, as described i keep getting error messages.