Spice simulation

original?

Hi Alex,

After your description I'm quite confident that it's an original part.
Below one more picture taken with other light.
As you can see the three circles are not that shallow.
Also the line across the upper right corner circle is clearly visible.

Thanks a lot.

Regards,
Edmond.
 

Attachments

  • c3601.jpg
    c3601.jpg
    84.8 KB · Views: 515
Disabled Account
Joined 2008
Re: Re: Re: Fairchild KSC3503/2SC3503 Model

Edmond Stuart said:


Does anyone know a source in Europe for these components?

Regards,
Edmond.

Hi Edmond

Have you tried this supplier?

Nikko Electronics UK

Hi Bob

Fairchild has a revised spice models for the SC3503 from 03.11 2008.
I have tried to get them, but it seems like Fairchild has some problems sending them.
You have to order the models by email, it usually takes seconds to receive them, but I ordered the yesterday and still no response.
Anybody else has the same problem?

Cheers
Stinius
 
Re: Re: Re: Re: Fairchild KSC3503/2SC3503 Model

stinius said:


Hi Edmond

Have you tried this supplier?

Nikko Electronics UK

Hi Bob

Fairchild has a revised spice models for the SC3503 from 03.11 2008.
I have tried to get them, but it seems like Fairchild has some problems sending them.
You have to order the models by email, it usually takes seconds to receive them, but I ordered the yesterday and still no response.
Anybody else has the same problem?

Cheers
Stinius


I'll try to get those models as well. However, bear in mind that my comments were directed in reference to the data sheet, not the SPICE model.

Cheers,
Bob
 
Re: Re: Re: Re: Fairchild KSC3503/2SC3503 Model

stinius said:
Fairchild has a revised spice models for the SC3503 from 03.11 2008.
I have tried to get them, but it seems like Fairchild has some problems sending them.
You have to order the models by email, it usually takes seconds to receive them, but I ordered the yesterday and still no response.
Anybody else has the same problem?

Yes, same exact problem here. I tried to get the 2sc5200 and 2sa1943 a day or two ago, but no luck.
 
i'm looking at the Vce/Ic chart and the slope of the Ib=60uA is approximately a 1mA per 100V slope. being that the slope follows a path ending at 10mA and 100V, this would give an approximate Early voltage of -1000V.

700 or so is probably a conservative figure, since by 2 different methods, 2 of us have come up with results that exceed the figure in the model, one of these estimates being almost twice the figure in the model.

actually, make that a 3rd method. rather than use the 60uA figure, i used the 50uA trace which at 100V is at 8.2mA, and just above 0V is at 7.5mA. this gives a slope of 0.7ma per 100V, which again calculates out to (if i did this right?) -1071V (or thereabouts, since the trace dives towards the origin abruptly at about 1 V)
 
Disabled Account
Joined 2006
Excellent figure of merit it may have, but it seems to me the nonlinear base collector capacitance plays a much bigger role defining the performance.

Edmond how many pairs do you need, I have now 2 agents in Asia trying to source as well as a member here in Hongkong, these devices are being replaced with smd types like this one 2sa1575 2sc4080, they have good performance but lousy power handling capabilities.
 
homemodder said:
Excellent figure of merit it may have, but it seems to me the nonlinear base collector capacitance plays a much bigger role defining the performance.

Hi Alex,

Generally, that's right, although in my specific application, the Early effect (VAF) has quite a lot of influence on the performance, at least according to my sim (FWIW).


Edmond how many pairs do you need, I have now 2 agents in Asia trying to source as well as a member here in Hongkong, these devices are being replaced with smd types like this one 2sa1575 2sc4080, they have good performance but lousy power handling capabilities.

Regrettably, I need them in a TO124 package because of the heat dissipation and thermal coupling as well (by means of stacking them together). Thanks for the offer anyhow.

I think I'll try the Fairchild trannies first. Maybe they are good enough.

Regards,
Edmond.
 
BB macromodels

Probably old news, but I just discovered this BB/TI document, regarding opamps (macro)models. It clearly describes the model types and limitations for each opamp.

http://focus.ti.com/lit/an/sbfa009/sbfa009.pdf

The nice thing is that some of these models can be taken as templates; it would then be possible to fill in the data (from data sheets and/or measurements) and get much missed models, like for the National power drivers LME4971x.
 
tnx. i recently typed in the model for a TLE2072 from the TI data sheet. as i did so i had to draw it out on paper just to make sure i was doing it right. i made a typo somewhere and it wouldn't work. so i looked at the one for the TL072. the models were almost identical except for the values of a few parameters. i made a modified copy of the TL072 and saved it as TLE2072.sub, and it worked. i finally did figure out where my typo was in the original copy that i typed up and it was something like putting a space in a parameter where it didn't belong (it sure looked like it was a space there in the data sheet).

now that i have the templates they use at TI, it makes things a whole lot easier. that was a great catch syn08:cheers:
 
Disabled Account
Joined 2008
Re: BB macromodels

syn08 said:
Probably old news, but I just discovered this BB/TI document, regarding opamps (macro)models. It clearly describes the model types and limitations for each opamp.

http://focus.ti.com/lit/an/sbfa009/sbfa009.pdf

The nice thing is that some of these models can be taken as templates; it would then be possible to fill in the data (from data sheets and/or measurements) and get much missed models, like for the National power drivers LME4971x.


Thank you syn08

Nice

Regards
Stinius
 
Wrong model

From the New York Times - Le Mode, March 14, 2009

"Dr. Merton and Dr Scholes won the Nobel in economic science in 1997 for the stock options model. Only a year later Long Term Capital Management, a highly leveraged hedge fund whose directors include the two Nobelists, collapsed and had to be bailed out to the tune of $3.65 billion by a group of banks"

So, beware of wrong models. :D
 
interestingly, there was a US government think tank paper that surfaced a few years ago that modeled economies as an op amp. it was mentioned in this paper that the use of feedback had far more effect on the output of the "amplifier" than did the actual inputs and "power supply". the paper then went on to describe how the feedback loops could be manipulated to cause instability (by adding "capacitive" or "inductive" delays) or crashed (latched to the rail). the paper was actually talking about using these various feedback mechanisms in economic warfare. it would be interesting to have an economist "model" the effect "government bailouts" and "economic stimulus" (by flooding state governments with money) to see what effect on feedback these "rerouted" "voltages" have. are these "voltages" being inserted on the inverting or noninverting input?

does it matter whether the model is correct? the output of the "amplifier" isn't just colored lines on a whiteboard, it's people's livelihoods.

it kind of bothers me that someone in an office in DC is running SPICE simulations of the economy using a 741 op amp model......
 
Hi all !

I am new here and i want to say hi ! All the folcks talk about spice and simulation , but ! The simulation is based on circuit schematic dyagram not on the finished product , that is the pcb , many things change after you build the pcb ! So my question is : Why thoes not exist a simulation software for the pcb's that wi design with cad software ???
All the best !
 
you can simulate the PCB in spice. just add the parasitic elements to the schematic. if you have an LCR meter, you can usually figure this out by measuring the unpopulated board. there will be some parasitic elements you won't get in this way (pin-to-pin capacitances of transistors, lead inductances, etc...), but you will get most of them. the rest of them can be measured on the component leads themselves. it just depends on what level of detail you want to go to.
 
Open loop measure

Hi

I am using method Middlebrook to simulate ( LoopGain2.asc in LTspice).

By this method I have to set the in open loop, gain= 1(RF1=1K and RF2=1K), I am sure ?
Measure open loop is with load or without load?

Thanks
Diagram:
 

Attachments

  • open_and_closed _loop.gif
    open_and_closed _loop.gif
    3.5 KB · Views: 639