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AD8130 Spice Model

Hi All

I would appreciate it if someone can help me with the following LTspice error.


Error on line 3 : u1 v1 0 v2 fb vcc vee fb ad8130
	 Unable to find definition of model "fb"
	*  Unknown parameter "vcc"
Fatal Error: URC instance U1: Length must be positive definite.

I'm trying to simulate the summing circuit application that is shown in the AD8129/AD8130 Datasheet on page 35. 

I have checked that my LTspice model pin list is in the same order as the "AD8130.cir" SUBCKT list.


R1 0 FB 1K tol=1 pwr=0.1
U1 V1 0 V2 FB VCC VEE FB AD8130
V1 V1 0 SINE(0 1 1K)
V2 V2 0 SINE(0 1 1K)
V3 VCC 0 12
V4 VEE 0 -12
.lib ad8130.cir
.tran 1m

I'm not sure if there is an error with the circuit or with my model. See the attached design files below.

Thank you

Updated file attached: Removed LOG.
[edited by: Lukkewaan at 9:42 PM (GMT 0) on 19 May 2020]
  • Hello Lukkewaan,

    The prefix in your symbol is wrong.
    Please open your symbol file(.asy) with the symbol editor and edit the attributes.
    You have set Prefix:U, but it has to be X.
    Change the prefix-value to X and save the symbol. Then place it again in the schematic.

    I have attached a zip-file with one of my examples.


  • Hi ,

    Thank you. I completely overlooked this. I thought it was just the prefix for the part.

    I have always subconsciously used X, not sure why I deferred from normal.

    Extract from LTspice Help

    The symbol's attributes can be overridden in the instance of the symbol 
    as a component in a schematic. For example, if you have a symbol for a 
    MOSFET with a prefix attribute of 'M', 
    it's possible to override the prefix to an 'X' on an 
    instance-by-instance basis so that the transistor can be modeled as 
    subcircuit instead.

    This article from Analog Devices also helped. Good to go back to basics - LTspice: Using an Intrinsic Symbol for a Third-Party Model

    Thanks again.

    Keep well.