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THS4541: The PSPICE model for ths4541 dose not work

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.



  • 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.


  • 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

  • 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.

  • 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.

  • 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

  • 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,

  • 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