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Original question:

THS4541: ths4541

THS4541: The PSPICE model for ths4541 dose not work

Howard Bandell
Intellectual 555 points
Part Number: THS4541
Other Parts Discussed in Thread: THS4531A

The pspice model does not work for this amplifier, THS4541 - tells me I have unconnected nodes inside amplifier.

  • 0
    Intellectual 555 points



    ERROR: Node U1:I0:I19:1:102 is floating and connected to current source G:U1:I0:I19:1:RA
    ERROR: Node U1:I0:I19:1:302 is floating and connected to current source G:U1:I0:I19:1:RC
    ERROR: Node U1:I0:I21:1:102 is floating and connected to current source G:U1:I0:I21:1:RA

    WARNING: Less than two connections to node U1:I0:I31:NET55.  This node is used by E:U1:I0:I31:AHDLINV0:1.
    WARNING: Less than two connections to node U1:I0:I30:NET55.  This node is used by E:U1:I0:I30:AHDLINV0:1.
    Direct Newton iteration for .op point succeeded.

    Date: Wed Oct 02 11:43:38 2019
    Total elapsed time: 0.125 seconds.


  • 0 in reply to Howard Bandell
    Guru 48395 points

    Well Howard, it is good that you are moving on to the much improved THS4541, try this .cir file - this is the TINA file (that I know works) simply saved out as a .cir. 

    THS4541_Pspice.CIR

  • 0 in reply to Michael Steffes
    Intellectual 555 points

    Same errors

    ERROR: Node U1:I0:I19:1:102 is floating and connected to current source G:U1:I0:I19:1:RA

    ERROR: Node U1:I0:I19:1:302 is floating and connected to current source G:U1:I0:I19:1:RC

    ERROR: Node U1:I0:I21:1:102 is floating and connected to current source G:U1:I0:I21:1:RA

    　

    WARNING: Less than two connections to node U1:I0:I31:NET55. This node is used by E:U1:I0:I31:AHDLINV0:1.

    WARNING: Less than two connections to node U1:I0:I30:NET55. This node is used by E:U1:I0:I30:AHDLINV0:1.

    Direct Newton iteration for .op point succeeded.

    　

    Date: Wed Oct 02 12:55:28 2019

    Total elapsed time: 0.063 seconds.

  • 0 in reply to Howard Bandell
    Intellectual 555 points

    I added 4 10 MEG resistors to ground at places in circuit that simulator was saying had only 1 connection.

    This seems to have fixed it.

  • 0 in reply to Howard Bandell
    Guru 48395 points

    Interesting Howard, 

    Yes, super high impedance nodes inside the model often cause problems. It was my impression this kind of thing was tested (running models in Pspice and/or LTspice) prior to release. I always added those 10M or 100M kind of values on difficult nodes in model development. 

    Maybe what happens in the TINA sims is a min conductance parameter is set in the options that adds these R's on those nodes automatically. There might be a similar PSpice option in the settings. 

    This thread gets into this, 

    https://e2e.ti.com/support/tools/sim-hw-system-design/f/234/t/742758

  • 0 in reply to Howard Bandell
    Prodigy 20 points

    Hi Howard, 

    i am having the same issue while trying to simulate THS4531A in LTspice. Could you please share the exact changes you made in your subcircuit? It would help me a lot.

    Thank you very much in advance. 

    Regards,

  • 0 in reply to Jon Clemente
    Intellectual 555 points

    I added 4 10 MEG resistors to ground at places in circuit that simulator was saying had only 1 connection.

    This seems to have fixed it.

    ERROR: Node U1:I0:I19:1:102 is floating and connected to current source G:U1:I0:I19:1:RA

    ERROR: Node U1:I0:I19:1:302 is floating and connected to current source G:U1:I0:I19:1:RC

    ERROR: Node U1:I0:I21:1:102 is floating and connected to current source G:U1:I0:I21:1:RA

    　

    WARNING: Less than two connections to node U1:I0:I31:NET55. This node is used by E:U1:I0:I31:AHDLINV0:1.

    WARNING: Less than two connections to node U1:I0:I30:NET55. This node is used by E:U1:I0:I30:AHDLINV0:1.

    XAHDLINV0 RECCIRSIGNAL NET55 VCC VEE HPA_INV_IDEAL
    R1000 NET55 0 10MEG
    *GE0 0 NET67 NET22 NET50 200

    GRA  101 102 VALUE = { V(101,102)/1e6 }
    CA  102 GNDF 1e3
    EB  1 1a VALUE = {V(102,GNDF)}
    R2000 102 0 10MEG


    G2  GNDF 3 VSS GNDF {GPSRRN}

    ED  3 3a VALUE = {V(302,GNDF)}
    R3000 302 0 10MEG


    E1  VO VI VALUE = {V(1a,GNDF) + V(3a,GNDF)}

    EA  101 GNDF 1 GNDF 1
    GRA  101 102 VALUE = {V(101,102)/1e6}
    CA  102 GNDF 1e3
    EB  1 1a VALUE = {V(102,GNDF)}
    R5000 102 0 10MEG

    E1  VI VO 1a GNDF 1