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Re: Looking for a IDT74CBTLV3253 model.

 

Hello Gunoi Nare

You are using an undocumented but officially approved for public use


Look at

and search for counter

Regards
PhB
Re: Modelling an optoisolator

 

Hello,
You could use a Bi or a Bv source with a table-function.

D1 is the diode of the optocoupler in this example.

Bi
I = table(I(D1), 0,0, 1m,0,5m, 10m,5m, 100m,20m)

Bv
V = table(I(D1), 0,0, 1m,1, 10m,4,9, 100m,4.95)

Best regards,
Helmut
Re: Looking for a IDT74CBTLV3253 model.

 

Gunoi Nare uploaded a circuit using the built-in "Counter" logic device.

Many of the logic devices require parameters, which you must attach or add to the device.? To add a parameter, right-click on the part, then type the desired parameter and its value, in the Value, Value2, SpiceLine, or SpiceLine2 fields.

The Counter device was not documented in the LTspice "Help" pages.? It was added somewhat recently to LTspice.? It is "documented" in a webpage about "undocumented LTspice", here:



According to that page, you have to provide at least the parameter named "Cycles", to tell the counter how many cycles to count.? Without that, the counter doesn't know what to do.

For example, right-click on the counter symbol, then click on the Value line (until you can type there), and type something like this:

cycles=4

Then press OK.

See the LTspice Help page for A-devices, to see some of the other common parameters for these logic devices (input levels, output levels, prop. delays, etc.).? By default these parts use 0V/1V levels.? You can list more than one parameter on the same line, such as:

cycles=4 ?Vhigh=5 ?Trise=10ns

Regards,
Andy
Re: Looking for a IDT74CBTLV3253 model.

Gunoi Nare
 

Thank you Helmut.

When Attempting to open de file the error:
"multiple instances of circle." is displayed.

In Fact all other file will do the same thing although the word "circle' is replaced by 'Flag" or some other indicator.

Is my program corrupt?

G.


From: "helmutsennewald@... [LTspice]"
To: LTspice@...
Sent: Monday, August 1, 2016 1:36 PM
Subject: Re: [LTspice] Re: Looking for a IDT74CBTLV3253 model.

?
Hello Gunoi,

Please take a look to the example file here. It shows how to use the digital devices in LTspice.

DIGITAL_A_DEVICES_1.ASC

?
?
EXAMPLE:
Place an AND
Right mouse click on it.?
A dialog will popup,

SpiceLIne: Vhigh=3.3 Vlow=0 Ref=1.65
SpiceLIne2: Td=1n Trise=1n

This AND has 0V/3.3V output, input threshold 1.65V, delay 1ns, rise and fall time 1n.


Use the nmos4 and pmos4 for the switch. Connect both in parallel as shown in the datasheet's schematic. Connect the substrate of the nmos4 to GND.?Connect the substrate of the pmos4 to VCC(3.3V).

Best regards,
Helmut
Re: Modelling an optoisolator

 

I am sorry.
...You must apply through a resistor negative bias...
You even specify the type of optocoupler.

Bordodynov.

02.08.2016, 08:05, "§¡§Ý§Ö§Ü§ã§Ñ§ß§Õ§â §¢§à§â§Õ§à§Õ§í§ß§à§Ó BordodunovAlex@... [LTspice]" <ltspice@...>:

Hey. You are probably accessing the telepaths. I do not know the elementary photodetectors elements having an output value of the line voltage. If the primary receiver is a pn junction, it produces current. Having loaded his resistance, can be obtained linearly varying voltage, before starting a pn junction. Neohodimo through resistor feeding a negative bias. For example, one pin resistor connected to the positive supply. See datasheet optocoupler.

Bordodynov.

02.08.2016, 07:19, "skip@... [LTspice]" <ltspice@...>:
I have a requirement to model an optoisolator in LTSpice. The optoisolator has an input LED that shines light on a photovoltaic cell on the output. Current in the LED will cause light to fall on the photovoltaic cell and cause a voltage to be generated on the output. I have measured the input-current-to-output-voltage characteristics of the device - Vout=F(Iin). The transfer function F is somewhat nonlinear. I have created a table of measurements listing the output voltage for a set of specific input currents. Now I am trying to build an LTSpice model that functions similarly to the actual device.

A simple first-order approximation of the device would be a current-controlled voltage source with the transfer function defined as a table. i have tried all kinds of ways to define the table in a LTSpice current-controlled-voltage-source, but no luck. Can anyone show me how to do this? What does the spice directive look like, and where (and how) do you put it in LTSpice?

A second-order model will need to take into account that output impedance will also affect the output voltage (at low impedances the output becomes more like ?a current source), but that is for another day.
Re: Modelling an optoisolator

 

Hey. You are probably accessing the telepaths. I do not know the elementary photodetectors elements having an output value of the line voltage. If the primary receiver is a pn junction, it produces current. Having loaded his resistance, can be obtained linearly varying voltage, before starting a pn junction. Neohodimo through resistor feeding a negative bias. For example, one pin resistor connected to the positive supply. See datasheet optocoupler.

Bordodynov.

02.08.2016, 07:19, "skip@... [LTspice]" <ltspice@...>:

I have a requirement to model an optoisolator in LTSpice. The optoisolator has an input LED that shines light on a photovoltaic cell on the output. Current in the LED will cause light to fall on the photovoltaic cell and cause a voltage to be generated on the output. I have measured the input-current-to-output-voltage characteristics of the device - Vout=F(Iin). The transfer function F is somewhat nonlinear. I have created a table of measurements listing the output voltage for a set of specific input currents. Now I am trying to build an LTSpice model that functions similarly to the actual device.

A simple first-order approximation of the device would be a current-controlled voltage source with the transfer function defined as a table. i have tried all kinds of ways to define the table in a LTSpice current-controlled-voltage-source, but no luck. Can anyone show me how to do this? What does the spice directive look like, and where (and how) do you put it in LTSpice?

A second-order model will need to take into account that output impedance will also affect the output voltage (at low impedances the output becomes more like ?a current source), but that is for another day.
Re: Looking for a IDT74CBTLV3253 model.

Gunoi Nare
 

Ok.... I uploaded it. "From G. .... "

G.


From: "Andy ai.egrps@... [LTspice]"
To: [LTspice] group
Sent: Monday, August 1, 2016 1:47 PM
Subject: Re: [LTspice] Looking for a IDT74CBTLV3253 model.

?
Gunoi Nare wrote:

? ?"yes I refer to the Digital lib.i attach here a simple counter .asc file . Please tell me what I do wrong."

No attached files!? They are removed by Yahoo's servers. ?(Apparently, a lot of other garbage was not removed.)

Please upload your .asc file to the "Temp" folder:



Andy
Re: Current Dependent Voltage Source

 

rmoreno.phone?wrote:

? ?"I've tried to understand how to create a current dependent voltage source but am unable to comprehend how to get my simulation circuit to work.? Is there anything available to describe in detail how to do this?"

Yes; there is the LTspice Help page for H-elements (current-dependent voltage sources).? But most of the reference descriptions there are most helpful for SPICE Netlists, and are a little vague about applying the same syntax to schematic symbols.

Assuming that you are using a schematic:

Voltage sources are our "ammeters".? Put a voltage source (probably set to 0V, but could be non-zero if that fits the rest of your circuit) in the branch where you want to sense the current, that will control your CCVS.

Add an H element where you want it.? Then right-click on the H that is by itself.? Edit that field so that it looks something like this:

Vxxx yyy.y

where Vxxx is the name (reference designator) of the voltage source that is the "ammeter",

and yyy.y is the transresistance or gain (in ?volts/amps) that you want.

Andy
Re: Current Dependent Voltage Source

 

Hello,

Please take a look to this example from our Files-section..



?

Best regards,

Helmut



H. Current Dependent Voltage Source

Symbol Name: H

Syntax: Hxxx n+ n- <Vnam> <transresistance>

This circuit element applies a voltage between nodes n+ and n-. The voltage applied is equal to the value of the transresistance times the current through the voltage source <Vnam>.

Syntax: Hxxx n+ n- value={<expression>}

This is an alternative syntax of the behavioral source, arbitrary behavioral voltage source, B.

Syntax: Hxxx n+ n- POLY(<N>) <V1 V2 ... V3> <c0 c1 c2 c3 c4 ...>

This is an archaic means of arbitrary behavioral modeling with a polynomial.

?
Modelling an optoisolator

[email protected]
 

I have a requirement to model an optoisolator in LTSpice. The optoisolator has an input LED that shines light on a photovoltaic cell on the output. Current in the LED will cause light to fall on the photovoltaic cell and cause a voltage to be generated on the output. I have measured the input-current-to-output-voltage characteristics of the device - Vout=F(Iin). The transfer function F is somewhat nonlinear. I have created a table of measurements listing the output voltage for a set of specific input currents. Now I am trying to build an LTSpice model that functions similarly to the actual device.?


A simple first-order approximation of the device would be a current-controlled voltage source with the transfer function defined as a table. i have tried all kinds of ways to define the table in a LTSpice current-controlled-voltage-source, but no luck. Can anyone show me how to do this? What does the spice directive look like, and where (and how) do you put it in LTSpice?


A second-order model will need to take into account that output impedance will also affect the output voltage (at low impedances the output becomes more like ?a current source), but that is for another day.
Need help to design a transimpedance amplifier

[email protected]
 

Hello ?guys..

I want to design a trans-impedance amplifier to detect currents of the APD (in the range of 200 nA to 100 micro A).

Could some one suggest me the best IC with less bias current, single supply (+5 V only) and how to design a high sensitive TIA..? (typically, for every 100 nA change in the current, 100 mV voltage should be displayed).
Current Dependent Voltage Source

 

I've tried to understand how to create a current dependent voltage source but am unable to comprehend how to get my simulation circuit to work.? Is there anything available to describe in detail how to do this?? It all seems confusing or incomplete.
Re: DanTherm model (SOAtherm)

 

I don't know anything about the model, but you could see if the MATLAB code runs under GNU Octave. It's a free open source tool meant to be m-code compatible.
Re: DanTherm model (SOAtherm)

[email protected]
 

I just discovered the LT application video on the SOAtherm-NMOS device. ?This looks like a really neat function. ?Searching the archives comes up with a thread from last year about converting datasheet information into SOAtherm models, but it looks like MatLab is needed. ?I'm not MatLab fluent (used it once, 20 years ago), but I'd like to model the FETs I'm using in my designs. ?Does anybody have any hints/tricks/recipes for determining the values of the entries in Dan Eddleman's DanTherm model? ?The library has these elements that determine the thermal model:

?

* The following two lines are customized for each DanTherm model *?
.param Tambient=85 RthetaJA=50 Cheatsink=0?
.param Imult=1.00E+01 Iexponent=3.00E-01 R6=3.18E-02 C6=1.77E-04 R5=1.01E-01 ?C5=2.77E-04 R4=2.74E-01 ?C4=1.60E-03 R3=8.49E-01 ?C3=8.83E-03 R2=7.34E-02 ?C2=3.30E-03 R1=1.05E-03 ?C1=1.82E-03

Do I need to contact Dan to get his modeling information?

Thanks,
Carl
libraries for electronic components

[email protected]
 

I need to simulate the following MOSFET in LTSpice: 2sk3577, RJK0632JPD and 2sk1580. Could you pass mee these components libraries?
Re: Looking for a IDT74CBTLV3253 model.

 

Gunoi Nare wrote:

? ?"yes I refer to the Digital lib.i attach here a simple counter .asc file . Please tell me what I do wrong."

No attached files!? They are removed by Yahoo's servers. ?(Apparently, a lot of other garbage was not removed.)

Please upload your .asc file to the "Temp" folder:



Andy
Re: Looking for a IDT74CBTLV3253 model.

 

Hello Gunoi,

Please take a look to the example file here. It shows how to use the digital devices in LTspice.

DIGITAL_A_DEVICES_1.ASC

?

?
EXAMPLE:
Place an AND
Right mouse click on it.?
A dialog will popup,

SpiceLIne: Vhigh=3.3 Vlow=0 Ref=1.65
SpiceLIne2: Td=1n Trise=1n

This AND has 0V/3.3V output, input threshold 1.65V, delay 1ns, rise and fall time 1n.


Use the nmos4 and pmos4 for the switch. Connect both in parallel as shown in the datasheet's schematic. Connect the substrate of the nmos4 to GND.?Connect the substrate of the pmos4 to VCC(3.3V).

Best regards,
Helmut
Re: Arcs in symbol editor

[email protected]
 

Thanks Helmut.
Re: Looking for a IDT74CBTLV3253 model.

Gunoi Nare
 

Danke Helmut

This is more than i bargained for :(

G.


From: "helmutsennewald@... [LTspice]"
To: LTspice@...
Sent: Sunday, July 31, 2016 2:01 PM
Subject: [LTspice] Re: Looking for a IDT74CBTLV3253 model.

?
Hello,

You could use the basic AND, NAND from the folder [Digital] plus a NMOS and PMOS transistor. See the circuit diagram in the datasheet.?

?

I recommend to make a hierarchical schematic. This means you make top-level schematic with your circuit and a lower level schematic with the IDT74CBTLV3253.

Best regards,
Helmut
Re: Looking for a IDT74CBTLV3253 model.

Gunoi Nare
 

Thank yu, Andy.
yes I refer to the Digital lib.i attach here a simple counter .asc file . Please tell me what I do wrong.
G



From: "Andy ai.egrps@... [LTspice]" <LTspice@...>
To: [LTspice] group <LTspice@...>
Sent: Sunday, July 31, 2016 6:00 PM
Subject: Re: [LTspice] Looking for a IDT74CBTLV3253 model.

? Gunoiar?wrote:

? ?"Also, I observe that the logic library contains only the graphical description on certain ?devices but lacks the simulation definitions."
I am confused what you mean by that.
Are you talking about the logic parts in the [Digital] section of the library?? They all have actual models already.? What's missing are the parameters that MAY need to be set, to get realistic performance.
I am not aware of logic parts in the LTspice library that are graphical symbols only.
Some analog parts, e.g., MESFETs, SCRs, IGBTs, valves/tubes, and varistors, are symbols only and you must provide the model.
Regards,Andy

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