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LTSpice LM13700 Simulation Error

Discussion in 'General Electronics Discussion' started by Yoa01, Jul 31, 2013.

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  1. Yoa01


    Jun 18, 2012
    Hello all,

    So I am trying to figure out how to properly simulate LM13700's without blowing up yet another chip (I've gone through 3 already - these get expensive!). I have LTSpice, so I figured I would grab an .asy of the LM13700 (this one), which I pasted into Notepad++ and saved as LM13700.asy in the lib/sym folder, and try it out.

    I built the Ramp/Pulse VCO schematic from the datasheet in LTSpice, but when I tried to run it I got this error:

    "Unknown subcircuit called in:
    xu1 n002 nc_01 0 n007 n008 n010 n008 n004 n005 lm13700/ns"

    Any ideas on how to fix this? If it helps (read: if I need to make an entirely new .asy), I have TI's SPICE model ( and know enough of SPICE programming to make things work.

    Thanks in advance.
  2. Harald Kapp

    Harald Kapp Moderator Moderator

    Nov 17, 2011
    The asy is only a grphic representation of the LM13700. You need to tell LTSPICE to use the model (subcircuit), or else it is unknown to LTSPICE.

    Here is a tutorial on how to integrate a subcircuit (the .MOD file) into an LTSPCE simulation.
  3. Yoa01


    Jun 18, 2012
    I thank you for that link. Though it directly did not help (call me stupid haha), it did lead me to find an alternate solution.

    For the curious, if you right-click the .subckt statement and click 'Create Model', LTSpice will generate a standard DIP-style IC that you can then edit.
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