Connect with us

PSpice Convergence Problem

Discussion in 'CAD' started by Bob Penoyer, Sep 15, 2005.

Scroll to continue with content
  1. Bob Penoyer

    Bob Penoyer Guest

    I have a circuit comprising one OP-77/AD op-amp that is basically a
    Sallen-Key filter with some other resistors and capacitors around it.
    All capacitors use a tolerance (10%) and all resistors use both a
    tolerance (1%) and a tempco (100 ppm/C).

    I've had convergence problems during worst-case simulations at some
    temperatures. The OP-77/AD seems to be at the heart of the problem but
    I'm stuck with it because I'm analyzing an existing circuit.

    All of the power supplies (+/-15V for the op-amp, and +5 for another
    item) have both 5% voltage tolerances and 200 mVpp noise at 20 kHz

    I've made these modifications to the default simulation settings:
    VNTOL = 1E-4
    ABSTOL = 1E-10
    GMIN = 1E-9
    ITL1 = 5000
    ITL2 = 2000
    ITL4 = 2000

    Is there something else I should do to enhance convergence?

    What about the solver? Is the default best? What are solver 0 and
    solver 1?

    Is selecting GMIN stepping helpful?


    Bob Penoyer
  2. Jim Thompson

    Jim Thompson Guest

    SOLVER=0 is the old original solver before it was "new and improved".
    I have found the setting SOLVER=0 will often work on difficult
    Sometimes ;-)

    ...Jim Thompson
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day