 Yeah, ladies and gentlemen, I want to give you a short update on the ng-spice development and Have some application Which I was dealing in the recent past is Electrothermal simulation Well, my name is Holger Vogt. I'm from University of Duisburg, Essen in Duisburg in Germany, and I'm also with a Fraunhofer Institute on microelectronic circuits and systems Okay, yeah, just to wrap up ng-spice. What is it? It's a circuit simulator it shows the equations of Electronic circuits and these electronic circuits may be made of passive and active devices and We want to solve the equations for time-varying currents and voltages and it's well its name says it It's the open source successor of the venerable spice 3 from Berkeley Well, what do we have? In fact, we have a circuit on the far left simple circuit here in CMOS inverter But this is not the input spice typically has because it's a command line input And we use of this thing in the middle just a list a net list which gives us the devices and the connections and Some simulation commands and the output is on the right This is a graphical output of for example where voltage is versus time You see some pulse pulse waveforms input and output of an inverter Okay, so and you spice has two major application areas It's the one is a PCB design support Well, typically here circuits are made of a mix of ICs and discrete components And there you have a requirement. Well, you have a comfortable user interface Okay, you have seen Angie Spice is Command line. So this is not that comfortable. So we rely on others we rely on key cut and We rely on some other parties to offer for example schematic capture and when we do these Circuit simulations we have to be compatible to some Well-known software tools like P-spice and LT-spice. This is mostly concerning the device models we are using on the other hand we have the capability of doing IC design support mostly today ICs are made of MOS devices and You have many of them and you would have some parasitic devices as well, of course resistors and capacitors That are included in your circuit There we need compatibility to existing device models Berkeley models BISM 3 and 4 and maybe BISM bulk and others and We have to have large circuit capability a few thousands or even 10,000 of transistors Therefore we need to certain simulation speed and we should be compatible to some process development kits that are offered by the foundries. So you get their device models from the foundry and Typical software used there is H-spice, so we try to be H-spice PDK Compatible and in red and down you see some software using NG-spice and supporting NG-spice both on the PCB Design support side and also on the IC design support side Okay, so what is the status or what we are doing right now? So we are working towards NG-spice 32 Should be available. Hopefully in March Well, as you see from the things we are doing there, there is no revolution going on. It's a lot of evolutionary development moving on Improved graphics for the output both on Windows and both on Linux We want to add unicode support that we use UTF-8 Strings and white charge strings on Windows and that we can use Korean and Chinese and Russian and other language Languages or texts for plots, node names, file names, directory names And we have a compared to the last NG-spice issue a revised model for PowerMOS devices An efficient model, this is the 3DMOS model and this now includes self-heating and I will talk about that in a minute Well in addition, of course, we have a lot of Enhancement of robustness, bug fixes Improved error handling. So if there is an error get better error messages Major code cleanup is in in fact going on and therefore the Yeah, the interconnection to to users Maybe on the kick-out side, maybe direct users and of NG-spice are important to react and we are relatively fast Sometimes bugs are fixed within one day if required Okay, some just some impressions. Well What how to input things into NG-spice now for example? We are kick-at while the power amplifier Schematic here and you can directly get the net list out of kick-out into NG-spice and either use the Internal kick-out NG-spice version or can you can offload it to external kick-out? Well and concerning IC work there is a relatively new thing called X-scam and Integration work is going on there also for IC work. Well, and the output is lots of different graphs It's new plot output. It's the internal NG-spice plotting capability. We can write post script files and we can of course use of the kick-out Integrated output Okay, so I have been Saying that I want to go a little bit into one special application area This is electrothermal simulation starting well with a if you are familiar with the MOS devices You see this output characteristics of an MOS device X-axis is drain voltage Y-axis is the current and what is happening? Well, you increase the drain voltage and the current is decreasing somehow This is strange. Yeah, do we have negative resistance in our MOS device? No, it's a very simple thing this device heats up and Because we have of course we have some power dissipation you see 10 volts and 2 amps 20 watt Power dissipation in device the device heats up and so the electrical characteristics of this device is changing Especially here the mobility of the charge carriers is decreasing and so the current decreases with increasing Temperature simply and the temperature increases because the power Disappointed power by increase Yeah, and so how can we do this? How can we model this and this is the idea we want? We have integrated recently into our devices. Yeah No, the gate watch which is a step. Okay, so Yeah, the question was to keep the gate voltage constant. No, I don't This is stepwise increasing in gate wattage here. Yeah, so the lowest graph is the lowest gate wattage and it's just raising up Yeah, so this is about electro thermal modeling and what is it yeah We make use of the equivalents of thermal circuits and electronic circuits Yeah, you be translate thermals into electrical circuits And then we run both circuit parts in ng-spice So electrical power dissipation generates heat Heat has some restricted flow path and so it rises to the temperature of the device temperature changes Some device characteristics and so we have these closed loop. This has to be integrated and well Deserves special device models that can react to this and in the table you see Okay, the equivalents of electrical and thermal terms like the heat capacitance Capability of a material to store heat similar as electric capacity electrical capacitance or we have the conductance Thermal conductance the heat flow is restricted somehow the same Equivalent as resistor for the electrical current. Yeah, and so because we can do Electronic and thermal circuits at the same time. Well, we can you simulate them at the same time here? You see just another power amplifier Made in a key cut is schema for generating the ng-spice net list and you see the MOS devices and these ms devices the power devices on the right Well on here. They're a little bit special because they don't have only three Pins, but they have five pins and they have three electrical and two thermal pins Thermal pins that the junction temperature and is the outer case temperature Yeah, so this is the interconnection between the electronic and the thermal Circuitry and on the right you see well This is our thermal circuit and in fact this is a heat Electrical equivalent of a heat sink you have a small resistor Coming in here. This is how the transistor is put on to the heat sink with some Some some glue or whatever had a certain thermal resistance Then we have a capacitor because of the mass of the heat sink that has a thermal thermal capacitance and you have a resistor The thermal resistance of this heat sink and then we have a voltage source. This is the outside temperature 42 degrees here and then you can do this Simulation because it's now all electrical Devices and of course and G-spice can do this and in the complete single fashion Well on the left you don't see much about these temperatures is just the input voltage and the output voltage So the amplifier is amplifying this is great and on the right you see a simulation for about 10 seconds 10 seconds on the x axis and the output well here It's named voltage, but in fact, it's the temperature you see here You just see the temperature of this Transistor on its heat sink is rising. Well, and we have the outside case temperature here And we have the junction temperature here and typically junction temperature is specified in the the specification sheet to We Not be the yarn the certain maximum and this can be simulated here easily now With a co-simulation of electrical and thermal circuits Okay, and you can do other thing. This is a resistor a simple resistor with has a negative Temperature coefficient that means the temperature rises so in the resistance decreases And we put a voltage on and we simulate versus time And we see where the temperature is rising and it's rising and rising and a certain point The thing breaks down the temperature goes up beyond all bounds and this is simply a thermal runaway Yeah, and so you can simulate The limits of your system system capability before it starts to explode let's say Okay, so to summarize well energy spice Hopefully will be available in March this year with several new features many many backfixes Unicode compatibility Enhanced Monte Carlo simulation capability. I didn't talk about this here today But this is another thing of interest especially for the IC designers and we have these electro thermal models of Power devices integrated and even then well, we just think about what will we do next for energy spice 33? Thank you Yeah, this is oh the question is where do I get the modeling data because the models are as as good as Well the data input data are Yes One has to look a little bit into detail. So for the transistor itself. It's just a So so judgment how much copper is in how much plastic is in and then you have weight and then you have its thermal Capacities of the material and then you can calculate the thermal capacitance for a heat sink. Well the heat sink heat sink manufacturer deliver these things to you Do you have to do that or is there a No, yeah, the question was is there in is it a native way of Doing some electrothermal simulation and he cut especially because on the graph it was voltage and in fact it was temperature Not yet the it's just a matter of these interface between a key cut and energy spice So energy spice in fact does calculate voltages and then you can tell of course the graph the output It's not a voltage. It's a temperature because the equivalence is clear and the the equations Relationship between these two is clear and so and he spice calculates voltage, but in fact It's the temperature and the graph should show temperature. Yes In within in g-spice directly you can just tell it. This is not a voltage. This is the temperature the question is can one take a cadence a Simulation environment the data and put them into ng-spice and to simulation Yes, there has been some guy doing a translator that use it takes the cadence Spectra input thing and translate it into the ng-spice netlist and the models of course you have to to select ng-spice had a certain Number of models available and if these are the same as cadence and well BZM 3 For older processes BZM 4 for newer processes, then you can do that or the question was Compatibility between LT spice and ng-spice and especially polynomial functions whether is a polynomial function capability in ng-spice as has been in the old spice to the same Same feature same function. This is working Well, if you say if it's fully compatible, well, we are never Fully compatible main reason is we don't know what LT spice has in yeah So we don't know the equations of LT spice so we can just figure out should be similar And this is what we are doing and this is continuously improving The question is what is the licensing situation of the the models Good question Well the Model development is mostly nowadays done proprietary these we are companies pay for these model development and models are Publicized some with some delay maybe a year or two also on the open world And there is I think model developers have and their The companies have agreed upon So-called I don't know the abbreviation educational license to and now they offer this models under this specific license. This is a sort of open-source license I Just have to clarify if it is Debian compatible because these are the very strict people will do that and If this is difficult well, then we have two distribution channels We have NG Spice and we have another download for If especially for Debian people and we have another download on the models and you can link it together So both are open source But maybe not the ultimate most newest model is available right now. Let's take what a year or two So