Errors running Pspice models in LTspice - Page 1
Forum section: electronics / beginners

author: Peabody
author_rank: Super Contributor
timestamp: December 28, 2021, 04:14:39 am
content: I see in various posts and in Youtube videos that Pspice models work in LTspice. But I have not found that to be the case. An example is the MCP6041 opamp, with Pspice model downloaded directly from Microchip. In a simple circuit, it fails. It can't find the .op. Iteration limit reached.Everything works fine using the LT1494, which is a very similar part, but of course the model for it comes with LTspice.Is there any way to do a translation so these Pspice models will work? I was kinda hoping someone would have written that script by now. Anyway below is the model and the log file of the aborted run. I used the opamp2 footprint, and confirmed that the pinout is correct.Code:.SUBCKT MCP6041 1 2 3 4 5* | | | | |* | | | | Output* | | | Negative Supply* | | Positive Supply* | Inverting Input* Non-inverting Input********************************************************************************** Software License Agreement ** ** The software supplied herewith by Microchip Technology Incorporated (the ** 'Company') is intended and supplied to you, the Company's customer, for use ** soley and exclusively on Microchip products. ** ** The software is owned by the Company and/or its supplier, and is protected ** under applicable copyright laws. All rights are reserved. Any use in ** violation of the foregoing restrictions may subject the user to criminal ** sanctions under applicable laws, as well as to civil liability for the ** breach of the terms and conditions of this license. ** ** THIS SOFTWARE IS PROVIDED IN AN 'AS IS' CONDITION. NO WARRANTIES, WHETHER ** EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED ** WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO ** THIS SOFTWARE. THE COMPANY SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR ** SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER. *********************************************************************************** The following op-amps are covered by this model:* MCP6041,MCP6042,MCP6043,MCP6044** Revision History:* REV A: 07-Sep-01, Created model* REV B: 27-Aug-06, Added over temperature, improved output stage,* fixed overdrive recovery time* REV C: 09-Apr-07, Adjusted quiescent current to match spec* REV D: 27-Jul-07, Modified output impedance at expense of comparator operation* to correct transient response with capacitive load** Recommendations:* Use PSPICE (other simulators may require translation)* For a quick, effective design, use a combination of: data sheet* specs, bench testing, and simulations with this macromodel* For high impedance circuits, set GMIN=100F in the .OPTIONS statement** Supported:* Typical performance for temperature range (-40 to 125) degrees Celsius* DC, AC, Transient, and Noise analyses.* Most specs, including: offsets, DC PSRR, DC CMRR, input impedance,* open loop gain, voltage ranges, supply current, ... , etc.* Temperature effects for Ibias, Iquiescent, Iout short circuit* current, Vsat on both rails, Slew Rate vs. Temp and P.S.** Not Supported:* Chip select (MCP6043)* Some Variation in specs vs. Power Supply Voltage* Monte Carlo (Vos, Ib), Process variation* Distortion (detailed non-linear behavior)* Behavior outside normal operating region** Input StageV10 3 10 -500MR10 10 11 69kR11 10 12 69kC12 1 0 6PC11 11 12 95PE12 71 14 POLY(6) 20 0 21 0 22 0 23 0 26 0 27 0 2.00M 10 10 29 29 1 1G12 1 0 62 0 1mM12 11 14 15 15 NMIG13 1 2 62 0 20uM14 12 2 15 15 NMIG14 2 0 62 0 1mC14 2 0 6PI15 15 4 4UV16 16 4 -300MGD16 16 1 TABLE {V(16,1)} ((-100,-1p)(0,0)(1m,1u)(2m,1m))V13 3 13 -300MGD13 2 13 TABLE {V(2,13)} ((-100,-1p)(0,0)(1m,1u)(2m,1m))R71 1 0 20.0E12R72 2 0 20.0E12R73 1 2 20.0E12I80 1 2 500E-15** Noise, PSRR, and CMRRI20 21 20 423UD20 20 0 DN1D21 0 21 DN1I22 22 23 1NR22 22 0 1kR23 0 23 1kG26 0 26 POLY(2) 3 0 4 0 0.00 -79.4U -39.8UR26 26 0 1G27 0 27 POLY(2) 1 0 2 0 0 26u 26uR27 27 0 1** Open Loop Gain, Slew RateG30 0 30 12 11 3.2R30 30 0 1.00KI31 0 31 DC 338R31 31 0 1 TC=2.25M,-15UGD31 30 0 TABLE {V(30,31)} ((-100,-1n)(0,0)(1m,0.1)(2m,2))I32 32 0 DC 535R32 32 0 1 TC=2.02M,-11UGD32 0 30 TABLE {V(30,32)} ((-2m,2)(-1m,0.1)(0,0)(100,-1n))G33 0 33 30 0 1mR33 33 0 3KG34 0 34 33 0 1R34 34 0 1KC34 34 0 100MG37 0 341 34 0 1mR341 341 0 1kC341 341 0 1.3NG371 0 37 341 0 1mR37 37 0 1KC37 37 0 3NG38 0 38 37 0 1mR38 39 0 1KL38 38 39 13ME38 35 0 38 0 1G35 33 0 TABLE {V(35,3)} ((-1,-1n)(0,0)(3.4k,1n))(3.5k,1))G36 33 0 TABLE {V(35,4)} ((-3.5k,-1)((-3.4k,-1n)(0,0)(1,1n))** Output StageR80 50 0 100MEGG50 0 50 57 96 2R58 57 96 0.50R57 57 0 101kC58 5 0 2.00PG57 0 57 POLY(3) 3 0 4 0 35 0 0 10U 1.49U 9.1UGD55 55 57 TABLE {V(55,57)} ((-2m,-1)(-1m,-1m)(0,0)(10,1n))GD56 57 56 TABLE {V(57,56)} ((-2m,-1)(-1m,-1m)(0,0)(10,1n))E55 55 0 POLY(2) 3 0 51 0 -0.7M 1 -40ME56 56 0 POLY(2) 4 0 52 0 0.6M 1 -55MR51 51 0 1kR52 52 0 1kGD51 50 51 TABLE {V(50,51)} ((-10,-1n)(0,0)(1m,1m)(2m,1))GD52 50 52 TABLE {V(50,52)} ((-2m,-1)(-1m,-1m)(0,0)(10,1n))G53 3 0 POLY(1) 51 0 -4U 1MG54 0 4 POLY(1) 52 0 -4U -1M** Current LimitG99 96 5 99 0 1R98 0 98 1 TC=-6.9MG97 0 98 TABLE { V(96,5) } ((-11.0,-3.9M)(-1.00M,-3.87M)(0,0)(1.00M,3.23M)(11.0,3.26M))E97 99 0 VALUE { V(98)*((V(3)-V(4))*1.39 + -1.5)}D98 4 5 DESDD99 5 3 DESD** Temperature / Voltage Sensitive IQuiscentR61 0 61 1 TC=2.52M,-4.31UG61 3 4 61 0 1G60 0 61 TABLE {V(3, 4)}+ ((0,0)(700M,5.3N)(770M,10.0N)(1.00,480N)+ (1.5,500N)(3.5,530N)(7.00,580N))** Temperature Sensistive offset voltageI73 0 70 DC 1uAR74 0 70 1 TC=1.5E75 1 71 70 0 1** Temp Sensistive IBiasI62 0 62 DC 1uAR62 0 62 REXP 210U** Models.MODEL NMI NMOS(L=2.00U W=42.0U KP=20.0U LEVEL=1 ).MODEL DESD D N=1 IS=1.00E-15.MODEL DN1 D IS=1P KF=0.2F AF=1.MODEL REXP RES TCE= 9.ENDS MCP6041Code:Circuit: * C:\Users\Owner\Documents\LTspiceXVII\Draft3.ascInstance "m:u1:14": Length shorter than recommended for a level 1 MOSFET.Instance "m:u1:12": Length shorter than recommended for a level 1 MOSFET.Direct Newton iteration failed to find .op point. (Use ".option noopiter" to skip.)Starting Gmin steppingIncreasing initial diagonal Gmin to 100Increasing initial diagonal Gmin to 1000Gmin = 1000Gmin = 107.374Gmin = 11.5292Gmin = 1.23794Gmin = 0.132923Gmin = 0.0142725Gmin = 0.0015325vernier = 0.5vernier = 0.25vernier = 0.125Gmin = 0.000994589vernier = 0.0625vernier = 0.03125vernier = 0.015625vernier = 0.0078125Gmin = 0.00100011vernier = 0.00390625vernier = 0.00195313vernier = 0.000976563vernier = 0.000488281Gmin = 0Gmin = 0Gmin stepping failedStarting source stepping with srcstepmethod=0Source Step = 3.0303%vernier = 0.25Source Step = 0.0177557%Starting source stepping with srcstepmethod=1Source Step = 3.0303%vernier = 0.25Source stepping failedPseudo Transient failed in finding the operating point at 11.25 µs.Fatal Error: Analysis Failed: Iteration limit reached

author: Terry Bites
author_rank: Super Contributor
timestamp: December 28, 2021, 06:43:05 pm
content: https://youtu.be/ajcYYwoHF0g?t=7m12sI hate LTSPICE, I gottta say. Its schematic entry is just bonkers.

author: Peabody
author_rank: Super Contributor
timestamp: December 28, 2021, 06:57:18 pm
content: Thanks but I've already done all the stuff in the video. The problem is that the third-party model simply doesn't work. I was hoping there was a simple way to change it to make it work.

author: Bud
author_rank: Super Contributor
timestamp: December 28, 2021, 07:12:08 pm
content: I've seen that,too. There was nothing that could be done in LTSpice to make it work and the same model worked just fine in TI Tina simulator. I concluded it was LTSpice glitch.

author: bson
author_rank: Unknown
timestamp: December 29, 2021, 05:12:50 pm
content: Doesn't LTspice treat 'm' (milli) as 'M' (mega)? It might be worth a try to remove all use of the 'm' SI suffix in the subckt.

author: tooki
author_rank: Super Contributor
timestamp: December 29, 2021, 10:40:50 pm
content: Quote from: bson on December 29, 2021, 05:12:50 pmNo. m is milli, and meg is mega. The problem is that when you type M (uppercase), it converts it to lowercase m. This has tripped me up several times.