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Hi Andy


On 07/10/2013 12:10 PM, Andy wrote:

The TVS may be sufficient. Like you say, they are meant to handle short
spikes, and that might be all that it ever sees ... ignition noise and
such. The instantaneous power could be up there but it's not wide enough
to heat up the device. The simulated waveform is probably very
pessimistic.

Hmmm, load dumps can last a looong time.
The large inductance field has to decay before
the alternator stops producing the over voltage.
100s of mS, long enough to fry the TVS?

Sorry for continuing OT.

Al D.


--


AC2CL

I do not think there is any thrill that
can go through the human heart like that felt by the inventor as
he sees some creation of the brain unfolding to success...
Such emotions make a man forget food, sleep, friends, love, everything.

- Nikola Tesla

--- In LTspice@..., Andy <Andrew.Ingraham@...> wrote:

I'm not quite sure what you are trying to achieve with that
expression, but I hope you know what you are doing there.

Er, um... homework?
___________________________

The invasion has begun... "Uhg-uhg. Brains, I need brains [drool]"

LTspice DOES NOT generate values at uniform sample times. So, "previous sample" (in the context of LTspice computation) makes little sense.


If you do want to evaluate in terms of a sampled data system, then you need to add a sample "clock" to your circuit and a sample/hold to the circuit. Then, process the S/H output.


Jim Wagner
Oregon Research Electronics

feabyl wrote:

How to implement an expression D(t)=D(t-1)+ a ?

Is that D(t-1) as in D(t - 1sec)?

If so, you can implement a 1 second time delay in either of two ways:

1. A (properly terminated) lossless transmission line (T-element) with a
delay of 1 second.

2. A behavioral source (B-element) with a delay of 1 second.

If the '-1' is supposed to represent the previous internal timestep in
LTspice, I don't think there is a way to do that. (But I'm not saying it
is impossible.)

Regards,
Andy

(PS: I'm not quite sure what you are trying to achieve with that
expression, but I hope you know what you are doing there.)

alzie wrote:

Ohms law says that your current is over 20A

Quite a lot for a little TVS.
Theyre usually meant for short spikes.

20A * 36V = 720W
That would convert youre TVS into a SED in short order.
(smoke emitting device)

You may need to use a real SCR crow bar and a fuse to be safe.

The TVS may be sufficient. Like you say, they are meant to handle short
spikes, and that might be all that it ever sees ... ignition noise and
such. The instantaneous power could be up there but it's not wide enough
to heat up the device. The simulated waveform is probably very pessimistic.

Andy

Hi eqmqiq


On 07/10/2013 01:44 AM, eqmqiq wrote:

Thanks for everyone's suggestion, I put a new TVS from the LTspice
library(SMBJ24CA) and set a series resistance(0.5 ohm) for the voltage
source.
the simulation result shows the voltage is clamped at 36V, but the
breakdown voltage of the TVS is 24V, I don't understand why...? wrong
parameter setting??
I update the asc file to TEMP folder with the same file name "
TVS_clamp.asc"

Ohms law says that your current is over 20A
Quite a lot for a little TVS.
Theyre usually meant for short spikes.

20A * 36V = 720W
That would convert youre TVS into a SED in short order.
(smoke emitting device)

You may need to use a real SCR crow bar and a fuse to be safe.


--


AC2CL

I do not think there is any thrill that
can go through the human heart like that felt by the inventor as
he sees some creation of the brain unfolding to success...
Such emotions make a man forget food, sleep, friends, love, everything.

- Nikola Tesla

--- In LTspice@..., "suri_bright" <nghoang_98@...> wrote:

Hi all, I would like to create the integrate and dump in LTspice
(the same with integrate and dump block in Matlab). I can create
the integrate by the equivalent idt() with bv.asv. However, I do
not know how to dump the signal. Is there any one know how to do
please help? Thanks

Yes, I do, but please go - go to where you may find the knowledge
of ALL the yummy, delicious brains forever preserved for your
eternal consumption in the great secret brain lockers known as
the group Message Archive and the Magical Help File. The key
password you will need is... "idt reset".

Now, go, go away. Begone o' Zombie.

PS: There are those who claim that homework zombieism may be cured
through much personal initiative, hard work and the willingness to
actually experiment with the brain-ware (i.e., LTspice). Yum!

The invasion has begun... "Uhg-uhg. Brains, I need brains [drool]"

Look at the line that starts the definition of the subcircuit.
?
?
.SUBCKT 06HPR33 1 2 3

You will notice that the subcircuit has 3 external nodes (1 2 3). The native inductor has only two external nodes. You cannot use the inductor symbol and assign this subcircuit to it because of the node mismatch. If you look in the Files section of this group,
?
Files > Tut > S-Parameter > S-Parameter to SPICE
you will find a symbol file for a 2-port device (S2PORT.asy). Your s-parameter file is a 2-port file as designated by the extension .s2p. You will notice that the 2-port symbol has three external nodes. Two of them connect to the nodes in your circuit where you would connect the inductor. The third node is ground.
?
?

________________________________
From: ayman_hendawy <ayman_hendawy@...>
To: LTspice@...
Sent: Wednesday, July 10, 2013 6:50 AM
Subject: [LTspice] import Touchstone file (s2p) to LTSpice

?
Hi,

I have ".s2p" files of some inductors and I need to import this file as a model to the inductors I have drawn in LTSpice in order to use it in the simulation, in order to do a practical simulation.

I downloaded the "s2spice_097.exe" from the "group files" and generate the .lib file, I get a file like this:
/***/
.SUBCKT 06HPR33 1 2 3
* MHz S MA R 50
* Z1=50.000000 Z2=50.000000

R1N 1 10 -5.000000e+001
R1P 10 11 1.000000e+002
R2N 2 20 -5.000000e+001
R2P 20 21 1.000000e+002

*S11 FREQ MAG PHASE
E11 11 12 FREQ {V(10,3)}= MAG
+( 1.000000e+006, 4.400000e-002, 2.585500e+001)
+( 1.047000e+006, 4.400000e-002, 2.681900e+001)
+( 1.097000e+006, 4.500000e-002, 2.780500e+001)
.
.
.
/**/

Then I added to my inductor in the spicemodel field: 06HPR33 , and add in the spice directive the following: .lib "the path to my .lib file".

But when I run the simulation I get nothing for the inductor, so kindly advice what I'm doing wrong.

Thanks

Hi all, I would like to create the integrate and dump in LTspice (the same with integrate and dump block in Matlab). I can create the integrate by the equivalent idt() with bv.asv. However, I do not know how to dump the signal. Is there any one know how to do please help? Thanks

Hi Ferdian Cahyodwiputro.
I created a small electronic circuit to test the model. Using this scheme, I found that the description of the transistor pins are in non-standard order. I will put circuit in the TEMP folder.
Bordodynov.

10.07.2013, 15:33, "Ferdian Cahyodwiputro" <ferdiancahyodwiputro@...>:

How to implement an expression D(t)=D(t-1)+ a ?

Hi Mr. Александр Бордодынов
can you upload this component? because i still can't understand to create new component..
i'm still newbe




________________________________
From: Ferdian Cahyodwiputro <ferdiancahyodwiputro@...>
To: "LTspice@..." <LTspice@...>
Sent: Wednesday, July 10, 2013 6:22 PM
Subject: Re: [LTspice] low noise amplifier



?
thank you..

this conversation helpfull my trouble.

________________________________
From: Александр Бордодынов <BordodunovAlex@...>
To: "LTspice@..." <ltspice@...>
Sent: Wednesday, July 10, 2013 5:06 PM
Subject: Re: [LTspice] low noise amplifier


?
==>HELP==>F.A.Q==>Third-party Models-->
.....
Example for a 3-pin NPN transistor but defined with a .SUBCKT statement:
.....

Bordodynov.

10.07.2013, 13:55, "Ferdian Cahyodwiputro" <ferdiancahyodwiputro@...>:

thank you for your information by the way so i must create new design symbol with this parameter?

________________________________
From: Александр Бордодынов <BordodunovAlex@...>
To: "LTspice@..." <ltspice@...>
Sent: Wednesday, July 10, 2013 12:21 PM
Subject: Re: [LTspice] low noise amplifier

Hi.
Model:

.SUBCKT q2SC5006_v111 7 8 9
Ccb 2 5 58f
Cce 2 6 87f
Cbe 7 9 0.67f
Cb 1 2 180f
Ce 2 3 180f
Lb 5 7 1.09n
Lc 2 8 0.79n
Le 6 9 0.99n
Lb2 1 5 0.004n
Le2 3 6 0.004n
Qnpn 2 1 3 q2SC5006_v111_M

.MODEL q2SC5006_v111_M NPN
+(IS=616e-18 BF=161 NF=0.99 VAF=50.0
+ IKF=1.5 BR=14.4 NR=0.99 VAR=2.4
+ IKR=0.32 ISE=38.2e-14 NE=2.19 ISC=80e-17
+ NC=1.0 RB=4.37 IRB=759e-6 RBM=2.23
+ RE=0.4 RC=5.0 CJE=2.21p VJE=0.954
+ MJE=0.408 CJC=1p VJC=0.667 MJC=0.408
+ XCJC=0.8
+ FC=0.50 TF=20.0e-12 XTF=1e-3 VTF=0.668
+ITF=9.7 TR=0 PTF=40 EG=1.11
+ XTI=3.0 XTB=0)
.ENDS q2SC5006_v111

Bordodynov.

10.07.2013, 08:20, "ferdiancahyodwiputro" <ferdiancahyodwiputro@...>:

dear everyone
i have toruble to design low noise amplifier.
i search transistor 2SC5006 in library LTspice but i can't found it.
please help me how to get transistor 2SC5006 in library LTspice

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]




[Non-text portions of this message have been removed]

thank you..

this conversation helpfull my trouble.




________________________________
From: Александр Бордодынов <BordodunovAlex@...>
To: "LTspice@..." <ltspice@...>
Sent: Wednesday, July 10, 2013 5:06 PM
Subject: Re: [LTspice] low noise amplifier



?
==>HELP==>F.A.Q==>Third-party Models-->
.....
Example for a 3-pin NPN transistor but defined with a .SUBCKT statement:
.....

Bordodynov.

10.07.2013, 13:55, "Ferdian Cahyodwiputro" <ferdiancahyodwiputro@...>:

thank you for your information by the way so i must create new design symbol with this parameter?

________________________________
From: Александр Бордодынов <BordodunovAlex@...>
To: "LTspice@..." <ltspice@...>
Sent: Wednesday, July 10, 2013 12:21 PM
Subject: Re: [LTspice] low noise amplifier

Hi.
Model:

.SUBCKT q2SC5006_v111 7 8 9
Ccb 2 5 58f
Cce 2 6 87f
Cbe 7 9 0.67f
Cb 1 2 180f
Ce 2 3 180f
Lb 5 7 1.09n
Lc 2 8 0.79n
Le 6 9 0.99n
Lb2 1 5 0.004n
Le2 3 6 0.004n
Qnpn 2 1 3 q2SC5006_v111_M

.MODEL q2SC5006_v111_M NPN
+(IS=616e-18 BF=161 NF=0.99 VAF=50.0
+ IKF=1.5 BR=14.4 NR=0.99 VAR=2.4
+ IKR=0.32 ISE=38.2e-14 NE=2.19 ISC=80e-17
+ NC=1.0 RB=4.37 IRB=759e-6 RBM=2.23
+ RE=0.4 RC=5.0 CJE=2.21p VJE=0.954
+ MJE=0.408 CJC=1p VJC=0.667 MJC=0.408
+ XCJC=0.8
+ FC=0.50 TF=20.0e-12 XTF=1e-3 VTF=0.668
+ITF=9.7 TR=0 PTF=40 EG=1.11
+ XTI=3.0 XTB=0)
.ENDS q2SC5006_v111

Bordodynov.

10.07.2013, 08:20, "ferdiancahyodwiputro" <ferdiancahyodwiputro@...>:

dear everyone
i have toruble to design low noise amplifier.
i search transistor 2SC5006 in library LTspice but i can't found it.
please help me how to get transistor 2SC5006 in library LTspice

[Non-text portions of this message have been removed]

Hi,

I have ".s2p" files of some inductors and I need to import this file as a model to the inductors I have drawn in LTSpice in order to use it in the simulation, in order to do a practical simulation.

I downloaded the "s2spice_097.exe" from the "group files" and generate the .lib file, I get a file like this:
/***/
.SUBCKT 06HPR33 1 2 3
* MHz S MA R 50
* Z1=50.000000 Z2=50.000000

R1N 1 10 -5.000000e+001
R1P 10 11 1.000000e+002
R2N 2 20 -5.000000e+001
R2P 20 21 1.000000e+002

*S11 FREQ MAG PHASE
E11 11 12 FREQ {V(10,3)}= MAG
+( 1.000000e+006, 4.400000e-002, 2.585500e+001)
+( 1.047000e+006, 4.400000e-002, 2.681900e+001)
+( 1.097000e+006, 4.500000e-002, 2.780500e+001)
.
.
.
/**/

Then I added to my inductor in the spicemodel field: 06HPR33 , and add in the spice directive the following: .lib "the path to my .lib file".

But when I run the simulation I get nothing for the inductor, so kindly advice what I'm doing wrong.

Thanks

==>HELP==>F.A.Q==>Third-party Models-->
.....
Example for a 3-pin NPN transistor but defined with a .SUBCKT statement:
.....

Bordodynov.

10.07.2013, 13:55, "Ferdian Cahyodwiputro" <ferdiancahyodwiputro@...>:

thank you for your information by the way so i must create new design symbol with this parameter?




________________________________
From: Александр Бордодынов <BordodunovAlex@...>
To: "LTspice@..." <ltspice@...>
Sent: Wednesday, July 10, 2013 12:21 PM
Subject: Re: [LTspice] low noise amplifier



?
Hi.
Model:

.SUBCKT q2SC5006_v111 7 8 9
Ccb 2 5 58f
Cce 2 6 87f
Cbe 7 9 0.67f
Cb 1 2 180f
Ce 2 3 180f
Lb 5 7 1.09n
Lc 2 8 0.79n
Le 6 9 0.99n
Lb2 1 5 0.004n
Le2 3 6 0.004n
Qnpn 2 1 3 q2SC5006_v111_M

.MODEL q2SC5006_v111_M NPN
+(IS=616e-18 BF=161 NF=0.99 VAF=50.0
+ IKF=1.5 BR=14.4 NR=0.99 VAR=2.4
+ IKR=0.32 ISE=38.2e-14 NE=2.19 ISC=80e-17
+ NC=1.0 RB=4.37 IRB=759e-6 RBM=2.23
+ RE=0.4 RC=5.0 CJE=2.21p VJE=0.954
+ MJE=0.408 CJC=1p VJC=0.667 MJC=0.408
+ XCJC=0.8
+ FC=0.50 TF=20.0e-12 XTF=1e-3 VTF=0.668
+ITF=9.7 TR=0 PTF=40 EG=1.11
+ XTI=3.0 XTB=0)
.ENDS q2SC5006_v111

Bordodynov.

10.07.2013, 08:20, "ferdiancahyodwiputro" <ferdiancahyodwiputro@...>:

dear everyone
i have toruble to design low noise amplifier.
i search transistor 2SC5006 in library LTspice but i can't found it.
please help me how to get transistor 2SC5006 in library LTspice

[Non-text portions of this message have been removed]

I got it, thanks for all your suggestions.

--- In LTspice@..., Kevin Cobley <kevin.cobley@...> wrote:

Having used LTSPICE for some years now, I never satisfactorily solved this issue:

I have some circuits that have essentially 0 gain, plotted on dB scales - I get 100's of dB on the vertical axis.

I can adjust the axis to display a meaningful range, but every time you run the simulator the scale is autoranged again. Clicking the tick box 'autorange' to not autorange is not effective here - every run get autoranged just the same.

Is there any way of locking the y axis to the entered values - I' sure I must just be missing something....and yes I read the documentation as best as I could...

Kevin.
________________________________
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Hello Kevin,

This topic comes up regularly (last week in fact). The solution to this is once you have adjusted the scales to your satisfaction, save the plot settings:

- Make sure the plot window is active
- Menu=>Plot Settings=>Save Plot Settings
- After each simulation, Menu=>Plot Settings=>Reload Plot Settings

It is very helpful to assign a hot key to this command - many people use the spacebar. To do this, from the control panel (hammer icon):

Waveforms tab=>Hot Keys

You can assign a large number of menu commands to hot keys; many are pre-assigned, by default.

Regards,
Tony

Important intuitive point - TVS does not have sharp breakdown like a zener.

Note, carefully Bordodynov's specs. Breakdown (probably at 10-100mA) of 26.7V to 29.5V. Conduction voltage rises 9V by the time the conduction current rises to 15.4A. Of course, no ordinary zener can handle that sort of current.

Jim Wagner
Oregon Research Electronics


On Jul 9, 2013, at 11:03 PM, Александр Бордодынов wrote:

All you get it right. Carefully study the documentation for the complete set.
Datasheet ---->
Breakdown Voltage Vbr=26.7- 29.5V,
Clamping Voltage Vc=38.9V at IPPM=15.4A

Bordodynov.

10.07.2013, 09:46, "eqmqiq" <g9512728@...>:

Thanks for everyone's suggestion, I put a new TVS from the LTspice library(SMBJ24CA) and set a series resistance(0.5 ohm) for the voltage source.
the simulation result shows the voltage is clamped at 36V, but the breakdown voltage of the TVS is 24V, I don't understand why...? wrong parameter setting??

I update the asc file to TEMP folder with the same file name " TVS_clamp.asc"

--- In LTspice@..., Andy <Andrew.Ingraham@...> wrote:

Everything said here is correct. The voltage source has precisely zero
output resistance, so it will sustain the driven voltage at whatever
current, no matter how hard the TVS tries to shunt it.

However, the other thing I find noteworthy is that your TVS is conducting
hundreds of amps even with the normal operating voltage (12.8V) when there
is no spike. I do not think you have set up its model parameters
correctly. Despite the fact that you have a TVS schematic symbol, the
parameters you gave it are for an ordinary silicon diode.

LTspice comes with two TVS diodes in its standard diode library. They use
different parameters than the ones you've specified.

Regards,
Andy


[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]