Setting LTspice up for use with Electric

Research Links

LTspice is provided courtesy of Linear Technology, Inc. and authored by Mike Engelhardt. Possible contact for topo.

A 180 Nanometer MOSFET Model – Using TSMC Transistor Models from MOSIS in LT Spice

If I use LTspice do I have to modify the SPICE models that I download from MOSIS? 

The models I download from CMOSedu.com work great with LTspice but I want to try some other technologies.

Yes, but you will have to change the

  • Change Level = 49 to Level = 8 for the BSIM3 models you download from MOSIS at: http://www.mosis.com/requests/test-data. 
  • For the BSIM4 models LTspice uses Level = 54 which is what MOSIS supplies so no change is needed.  

​In any case I would download the models, draft a ring oscillator, and compare the simulated oscillation frequency to the measured value reported by MOSIS in these files to verify that the models are working correctly.

 

Archive: The LTSPICE library file made up from MOSIS files and LTSPICE test analysis .asc file: 180nM-NMOS-PMOS-T92Y-MOSIS-LTSPICE-Files-V2.7z   

The archive file should work straight out of the box after extraction. Make a directory and extract to it.  It has the library file, symbols and an LTSPICE test circuit.

NOTE: When I vary the threshold voltage of the models with this version I do not see any changes in FET analysis.  I suspect something is not quite right with this setup.  No errors are flagged and everything runs.

 

Archive: This LTSPICE archive has model files that are used by using an nmos4 and pmos4 symbol.  Thus there is no subcircuit statements used in the library file.

NOTE: With this version  when I vary the threshold voltages I see the expected resultant change in the analysis output.

180nm analysis and model files 

The archive file should work straight out of the box after extraction. Make a directory and extract to it.  It has the library file, symbols and an LTSPICE test circuit.

Notes from the process follow. If you want to recreate the process for other MOSIS files they will be helpful.

Research Links

Model Files – No modifications. As is from MOSIS

Notes

  • To bring up the components attributes editor  for a part hold control button down and right click on the part.  Set the Prefix = X to set the components attributes editor to come up each time you right click on the part.

Auxiliary Links

Open Source Software: Timing Editor

I needed to draw a timing diagram for a mixed signal class I took.  I found 

The problem I was solving is shown below in the image.  It's rather tedious to figure out.  You have to remember that once a gate capacitance is charged up it ideally holds that charge until it is connected to again by either Vdd or Ground.

 

The gate turns out to be a falling edge triggered flip flop.  You can see it in the wikipedia:flip flop article that includes this diagram which was found after I did the timing diagram.

 

Agilent Application Note 1462 with ADS Design Files

Project Documentation and Files

Research Links

Files in Order of Usage in Application Note 1462

  • Step 2: Figure 3: FET_Gm_Calcs.sch
  • Step 3: Figure 5: FET_SP_NF_Match_Circ.sch
  • Step 4: Figure 7: Gain_and_Stab_DiscOpt.sch
  • Step 6: Figure 10: SP_NF_GainMatchK.sch
  • Step 7: Figure 12:  HB1Tone_LoadPullMagPh.sch
  • Step 8: HB1Tone_SourcePull.sch
  • Step 9: DA_LEMatch1_InputMatch1.sch

Once you have gone through the lower level blocks that make up the balanced amplifier the next step is to simulate the whole balanced amplifier subsystem.

BalancedLumpedAmp.sch

Orcad Schematic Capture and Board Layout Notes

Research links

 

Library Download Links

 

Methodology Example: Silicon labs methodology