Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

Recent content by garvind25

  1. G

    Plotting required waveforms in LTSPICE XVII

    Hi, I am trying to characterize the transistors for gm/Id design methodology. I am using LTSPICE for it and have the following queries. I hope someone can answer them: ** Can I define a constant capacitance value in LTSPICE such as Cox = 8.5fF/u^2 such that after simulation, I can...
  2. G

    How to extract Cgg from a SPICE model file

    Hi, I need to extract the value of Cgg from a given SPICE model file? How can I do it through simulations/ hand calculations pls? I am attaching the model file with this query. Many thanks, Arvind Gupta.
  3. G

    Plotting curves for gm/Id technique

    OK (and thanks for your quick reply). I will use xschem then. I have two queries aligned to it. 1. Should I use NGSpice with Xschem? Or does XSchem have a default simulator with it? 2. Are you aware of any tutorial which shows how to plot any of the above mentioned graphs? I am new to xschem...
  4. G

    Plotting curves for gm/Id technique

    Thanks for your reply. I have ngspice. But how to enter the schematic in it for plotting the various graphs? As I know, ngspice does not have any GUI for schematic entry. BTW are you aware if ngspice can be used with LTSpice interface? Regards, Arvind Gupta
  5. G

    Plotting curves for gm/Id technique

    Hi, I wanted to know if I can plot the various curves needed in gm by Id technique using LTSpice XVII. I basically need to plot the following curves for n channel and p channel devices: fT vs gm/Id gm/gds vs gm/Id Id/W vs gm/Id How can I do so using LTSPice? If it is not possible, pls...
  6. G

    32 bit version of NGSPICE

    Yes, i have the 32 bit version of NGSpice for windows. Then again, there is another problem - I dont have the 32 bit windows version of Xschem! Any ideas how to get it? Without a schematic editor, (practically) how do I define circuits..? Thanks and Regards, Arvind.
  7. G

    32 bit version of NGSPICE

    Hi, I have a 32 bit OS installed in my PC. Correspondingly, does NGSPICE have a 32 bit version pls? I could not find the 32 bit version of the latest release on sourceforge. If there is none, did NGSPICE ever release a 32 bit version in the past? Awaiting your response. Thanks, Arvind...
  8. G

    NGSpice integration with LTSpice or any other schematic designing GUI

    Hi, I am planning to use NGSpice for doing some simulations. However, since it is a non GUI based tool, can anyone pls tell me how to integrate NGSpice with a schematic design GUI – say LTSpice. If I remember correctly, there was a webpage somewhere which gave out the exact instructions on...
  9. G

    gm/Id value of pmos is more than 35

    Thanks for your reply. I dont have access to these PDKs. If I did, I would not have asked. I just need a PDK with which I can try out gm/Id technique.
  10. G

    gm/Id value of pmos is more than 35

    Hi all, Just checking back if anyone has a solution to my problem. I just need a PDK having Spectre support with near-to-real parameters (the one I have - gpdk90 is far away from a real pdk: gm/Id for pmos is above 41). Thanks and Regards, Arvind Gupta.
  11. G

    gm/Id value of pmos is more than 35

    Thanks for your reply. Unfortunately, I dont have HSPICE. Also if it is a CDK (Cadence Design Kit), I suppose it should support a Cadence Simulator (Spectre etc).
  12. G

    gm/Id value of pmos is more than 35

    Thanks for your reply. I had tried using NCSU FreePDK and NCSU CDK. However they don’t have spectre model files (.scs files) for simulations. Both of the PDKs have HSPICE compatible model files only. This is strange as at least NCSU CDK (CDK Stands for Cadence Design Kit) should have spectre...
  13. G

    gm/Id value of pmos is more than 35

    Ok. Then can you pls point me to any PDK (with install instructions) which I can use. Thanks in advance, Arvind
  14. G

    gm/Id value of pmos is more than 35

    Thanks for your reply. I plotted the gm and id curves separately (against sweeping vgs). At 0 v (vgs), the value of gm = 145n and id = 3.5n (snapshots attached). So gm/id = 41.42. This is as per the gm over id graph plotted directly (as per the snapshot in my first post). I am also...
  15. G

    gm/Id value of pmos is more than 35

    Hi, I am trying to plot gm/Id curve of a pmos in 90nm gpdk using Cadence. In it, when I use the ‘gmoverid’ signal directly available in the list, I am getting a max value of 41 (pls see attached snapshot). As I know, it cannot be more than 35 or 36 [as gm/Id = 1/ (n*Vt) = 1/(n*26mV) = 38.5/n...
See more

Part and Inventory Search

Back
Top