Electronics

LTSpice Math Functions and Manual

Research Links


Expressions can contain the following:

  • Node voltages, e.g., V(n001)
  •  Node voltage differences, e.g., V(n001, n002)
  • Circuit element currents; for example, I(S1), the current through switch S1 or Ib(Q1), the base current of Q1. However, it is assumed that the circuit element current is varying quasi-statically, that is, there is no  instantaneous feedback between the current through the referenced device and the behavioral source output. Similarly, any ac component of such a device current is assumed to be zero in a small signal linear .AC analysis.
  • The keyword, "time" meaning the current time in the simulation.
  • The keyword, "pi" meaning 3.14159265358979323846.
  •  The following functions:

….more

By Fudgy McFarlen, ago

MOSFET Extraction of Weak Inversion Parameters If: Normalization Current Vt Threshold Current N Body Factor Vp Pinchoff Voltage Lab Using Spice

 

This assignment was very difficult to finish because the lab had only one measurement device and the other teams were taking 3 to 4 days to figure out how to use it.  

Lab Assignment

If-Extraction   Threshold-Voltage-Extraction  Pinchoff-Voltage-Body-Factor

Brazil-Consulate-Stamp

 

By Fudgy McFarlen, ago

Low Voltage Schmitt Trigger Design in Weak Inversion Using LTSpice

The results of this project are probably wrong.  However SPICE and the Schmitt trigger circuit are all set up in the archive. If you find errors in the analysis or get better results somehow please come back and leave a comment detailing the error or linking out to your better analysis.

Low Voltage Schmitt Trigger Project Archive

Research Links

  • ECEN4827/5827 Analog IC Design – These notes from a course tell you how to set up a BSIM3v3 model and use in LTSpice circuit.  
  • Use of the NMOS symbol in LTSpice Local Copy – This link is from the page immediately previous link.  It has the specifics of using the library needed to use BSIM3v3
  • Introduction to LTSpice , Local Copy: MOSFET Device models used by SPICE (Simulation Program for Integrated Circuit Engineering) simulators can be divided into three classes: First Generation Models (Level 1, Level 2, Level 3 Models), Second Generation Models (BISM, HSPICE Level 28, BSIM2) and Third Generation Models (BSIM3, Level 7, Level 8, Level 49, etc.) The newer generations can do a better job with short channel effects, local stress, transistors operating in the sub-threshold region, gate leakage (tunneling), noise calculations, temperature variations and the equations used are better with respect to convergence during circuit simulation. In general first generation models are recommended for MOSFETs with gate lengths of 10um or more. If not specified most SPICE MOSFET Models default to level=1 (Shichman and Hodges) 
  • BSIM3v3.2.2 MOSFET Model ( Appears to be "the manual" )  
  • BSIM3 Archive – files can be downloaded here.  However at one point in the LTSPICE documents above they mentioned the MOSFET model or library was modified for usage with LTSPICE.  I do not know how much modification was required.
  • LTSPICE – Adding components.  

References

Notes

  • I have verified that the model works below mosfet threshold voltage by simulating an inverter at 0.300 Volts supply voltage. 
  • Transistor circuits become very slow as you lower their current.  Perhaps that is why I think so slowly.  I am guessing my neurological system is pretty low voltage.

Additional Links

By Fudgy McFarlen, ago

CI Brasil – CT1 Porto Alegre Inscription Open

Calendário CT1

  • 17/04/14         Início da Fase 1 – Abertura das inscrições
  • 22/06/14         Fim da Fase 1 – Fechamento das inscrições. 
  • 26/06/14         Início da Fase 2 – Prova online
  • 04/07/14         Fim da Fase 2 – Divulgação dos selecionados
  • 04/07/14         Início da Fase 3 – Início do envio de documentos
  • 18/07/14         Fim da Fase 3 – Último dia para envio da documentação POR SEDEX (data de postagem).
  • 12/07/14         Divulgação de vagas remanescentes
  • 04/08/13         Matrícula presencial
  • 05/08/14         Cerimônia de Abertura e Orientation Day (manhã)………..Início do Programa de Formação (tarde).
  • 31/07/15         Fim do Programa de Formação
By Fudgy McFarlen, ago

Book Review: Professor Van Nostrand: CMOS Analog Design Using All Region MOSFET Modeling

Research Links

The class taught by the author is centered around the ability to scale MOSFET's across technologies using normalization.   This is typified by the second question on the test given in the course.   

Test Page 2

Partial solution of question 2 – This solution derives part A & B W/L.  Part C is just plug and chug.

Laboratory where parameters are extracted using SPICE

By Fudgy McFarlen, ago

RF over Fiber

RF over fiber is where you modulate an RF signal onto the light beam and thus transmit it at a lower loss over a long distance.  It is an analog usage as opposed to a digital one as used in data transmission such as an ethernet extender. I have found some equipment for doing this but have not yet found anything that appears it will do the full Internet + Cable TV solution to extend the pole to internet modem solution that is cheap enough to use.

Research Links

Conclusions

For now this is not a viable solution to the house in the forest long internet cable extension problem.  It will probably get there soon though.

By Fudgy McFarlen, ago

Extending Ethernet Long Distances using Fiber Optic Media Converters

Research Links

 

The MC111CS and MC112CS are complimentary in that the Tx wavelength is the Rx wavelength of the other.  See excerpt below.

The MC112CS is a media converter designed to convert 100BASE-FX fiber to 100Base-TX copper media or vice versa. Adopting WDM technology, MC112CS takes only one fiber cable to transmit and receive data, which will save half cabling cost for you. Designed under IEEE 802.3u 10/100Base-TX and 100Base-FX standards, the MC112CS is designed for use with single-mode fiber cable utilizing the SC-Type connector. The MC112CS supports longwave (LX) laser specification at a full wire speed forwarding rate. It works at 1310nm on transferring data and at 1550nm on receiving data. So the other end device to cooperate with the MC112CS should work at 1550nm on transferring data and at 1310nm on receiving data. Another TP-LINK?s media converter MC111CS is just one of the examples to cooperate with MC112CS.

What are Media Converters

MC111CS & MC112CS Fiber optic media converter link

  • I tested this setup with a 120 foot long patch cord.  It worked.  

The parts inside the box

By Fudgy McFarlen, ago