AD8310 Logaritmic amplifier - can't get Vout reading
Hi,
?
I'm new to LTSpice. The learning curve is high, but I'm having fun.
?
I'm trying to see the Vout response of the AD8310 Logaritmic amplifier.
I chose C1, C3 and L1 so that the input has a band pass around 380 MHz, guessing the values as per the table in the datasheet of the AD8310.
Vout however stays flat for all frequencies.
What am I doing wrong?
?
?
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Re: Mixer equivalent model in ltspice
All the parasitic capacitances and
inductances, which are very important at such a high frequency,
as you must know, depend very much indeed on the physical layout
of an actual circuit, so a different LTspice model would be
needed for every physical circuit. You might be able to get a
SPICE model (not LTspice but compatible) from a manufacturer of
such mixer modules, but other simulators are specifically
designed for simulating at gigahertz frequencies.
On 2024-12-31 13:19, john23 via
groups.io wrote:
Hello , Is there a mixer model ?in ltspice ?which gets two RF
signals at 9.5 GHz .
which is realistic?
meaning The Lo needs to be 10dBm stronger then RF signals?
saturation ? Etc..
is there some such realistic mixer model at about 9.5 GHz?
Thanks.
--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
|
Re: Mixer equivalent model in ltspice
On Tue, Dec 31, 2024 at 08:19 AM, john23 wrote:
Hello , Is there a mixer model ?in ltspice ?which gets two RF signals at 9.5 GHz .
which is realistic?
There are many kinds of RF mixers.? (And of course I am discounting the other kinds of mixers, the linear ones to mix or add analog signals together.)? Some RF mixers have diodes and transformers, some have transistors, and it might be most accurate to model it exactly the way it is built - using transformers and the appropriate semiconductors.? Model it the way it really is.
?
RF mixers do a nonlinear function.? That part of what they do could be emulated with a 2- or 4-quadrant analog multiplier, which you can do in SPICE using a voltage multiplier, either an E-source or a B-source, and you would get the same effect of converting RF frequencies from RF and LO to IF.? But it would not be realistic because it would lack the intricacies of a real mixer.
?
You could try contacting the mixer manufacturer.? However, I suspect few if any have SPICE models in that frequency range.? Microwave engineers tend not to use SPICE.
Andy
?
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Re: Mixer equivalent model in ltspice
On 31/12/2024 14:19, john23 via
groups.io wrote:
Hello , Is there a mixer model ?in ltspice ?which gets two RF
signals at 9.5 GHz .
which is realistic?
meaning The Lo needs to be 10dBm stronger then RF signals?
saturation ? Etc..
is there some such realistic mixer model at about 9.5 GHz?
If you want a realistic model to work at 9.5GHz, you will have to
design it yourself. Honestly, although it possible to do such design
in LTspice, in principle, there are better tools available -
specifically, that support microwave transmission lines. Microwave
mixers are relatively complex, in that you have to model all
parasitics not only in the diodes, but also in whatever is used for
baluns, if indeed those are used.
You don't say what kind of mixer it is. Is it:
single-ended?
balanced?
double-balanced?
triple-balanced?
These will all have different internal construction.
Unless you are actually designing the mixers, it is unusual to
simulate them with "realistic" models. Most mixer suppliers provide
specifications, which include insertion loss, return loss on all
ports, and often a table of spurious products. All these will be as
measured on their physical testjig. Often, you can get a demo board
from suppliers, where you can make your own measurements.
To get a better answer, you will have to provide more information.
--
Regards,
Tony
|
Mixer equivalent model in ltspice
Hello , Is there a mixer model ?in ltspice ?which gets two RF signals at 9.5 GHz .
which is realistic?
meaning The Lo needs to be 10dBm stronger then RF signals?
saturation ? Etc..
is there some such realistic mixer model at about 9.5 GHz?
Thanks.
|
Re: Need help with 74LVC1G74 parameters
On 31/12/2024 13:13, Andy I via
groups.io wrote:
Most of those
models that have those three parameters, come with pre-made
LTspice symbols, perhaps in a separate .ZIP file.? They set up
those parameters automatically, so you don't need to.? Usually the
VCC parameter should be set by you somewhere in your simulation,
but the other two don't need to be changed,.
Here: 74LVC1G.zip
There is also an example Test
Schematic, albeit for the 74LVC1G86, in the same folder, which
shows how to use the library.
--
Regards,
Tony
|
Re: Need help with 74LVC1G74 parameters
Most of those models that have those three parameters, come with pre-made LTspice symbols, perhaps in a separate .ZIP file.? They set up those parameters automatically, so you don't need to.? Usually the VCC parameter should be set by you somewhere in your simulation, but the other two don't need to be changed,.
?
Andy
?
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Re: Can LTspice show Cross Over distortion of a class B type amplifiers...
On Tue, Dec 31, 2024 at 02:57 AM, <dlwarr911@...> wrote:
.... The only response I can give right now is that Yes I have a bread board circuit, signal generator, and scope which shows the cross over clearly on the Darlington pair... And, I love LTSpice .... So I was disappointed not to be able to see the distortion with LTspice...
Then it is likely that something is different between what you built, and what you simulated.? The simulation ought to match the hardware, if all things were equal.? Apparently something was not equal.
?
If the circuit is really class B with zero bias voltage, then I'm sure crossover distortion is happening, just not enough to see it easily.? But I wonder if the bias is not the same, or if the amp's negative feedback loop "eliminated" most of the visible distortion.? Either way, the simulation did not match the hardware, but it should.? Maybe not 100%, but pretty closely.
?
By the way, LTspice is spelled "LTspice", not "LTSpice".? And yes many of us agree it is a wonderful tool.
?
Andy
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Re: Need help with 74LVC1G74 parameters
Thanks so much for the clear explanations.? ?Now I know what I am doing.? I had speed set = 1 and tripdt =100p, but I didn't know why.
I am running a simulation right now using the 74LVC1G14 spice model.
?
Jim
?
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Re: Can LTspice show Cross Over distortion of a class B type amplifiers...
Thank you ALL for your input.... The only response I can give right now is that Yes I have a bread board circuit, signal generator, and scope which shows the cross over clearly on the Darlington pair... And, I love LTSpice .... So I was disappointed not to be able to see the distortion with LTspice... I've been in electronics since high school and am now 73y,,, LTSpice is such a wonderful tool...? ?
NOW I will go and use your advice to see if I can see my distortion.. again thanks, people like you make it a wonderful world...?
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Re: Need help with 74LVC1G74 parameters
On Mon, Dec 30, 2024 at 07:03 PM, Jim McLucas wrote:
* - VCC={VCC} Speed=1 Tripdt=100p
,,,
Do I use Speed=1 for 5V operation?? What do I use for Tripdt value?? What does Tripdt=100p mean?
Here is the way these three parameters are most commonly used in these (and similar) models:
- Speed allows you to choose a relative speed variation.? Speed=1 is for a nominal (typical) part.? It is independent of VCC.? You might try values such as Speed=0.7 or Speed=1.5, for slow or fast parts.
- VCC is the power supply voltage.? With luck, the model already changes its speed depending on the value of VCC, independently of the Speed parameter.
- The Tripdt parameter is a helpful convergence aid for some of the internal devices inside the model.? It suggests to LTspice that it should throttle the internal timestep to 100 ps or less when the signal is changing.? This helps prevent LTspice from advancing right through a change of state (low to high or high to low).? It's unlikely that you would need to change that parameter.
?
Andy
?
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Re: Need help with 74LVC1G74 parameters
Oops, I meant to say "74LVC1G74.
?
Jim
?
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Need help with 74LVC1G74 parameters
I need help setting up the 74LVC1g74 Flipflop parameters for 5V operation.
From the 74LVC1G.lib file I get the following information:
_________________________________________________________________________________________________________
* Delays have been adjusted for Vcc = 1V8/2V7/3V3/5V (LVC) using the test conditions stated in the
* Nexperia data sheets, and generally achieve Tpd errors less than 10%. The actual VCC voltage needs
* to be passed to each device as a parameter, either a fixed value, or a variable by placing:
*
* - VCC={VCC} Speed=1 Tripdt=100p
*
* in the Value field of the symbol, where {VCC} denotes that it is defined somewhere in the schematic.
*
* Temperature effects are currently not modelled.
*
*
______________________________________________________________________________________________________________
?
Do I use Speed=1 for 5V operation?? What do I use for Tripdt value?? What does Tripdt=100p mean?
?
Your help will be much appreciated.??
Thanks,?
Jim
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Re: Can LTspice show Cross Over distortion of a class B type amplifiers...
In order to tune crossover distortion, the best is visualizing
linearity. Distortion percentage doesn't indicate what to adjust.
Le 30/12/2024 ¨¤ 16:46, aledelaplaza via
groups.io a ¨¦crit?:
toggle quoted message
Show quoted text
To evaluate
and quantize crossover distortion you can use a notch filter
(RC bridge) to eliminate the fundamental frequency out of the
output voltage.
I have uploaded an example schematic
featuring the Quad 303 output stage.
--
Regards,
Tony
On 30/12/2024 11:56, Tony Casey wrote:
You can also do this with a .DC
analysis. With this it's also very easy to do a
"wingspread" plot, which plots the incremental gain, which
is very revealing.
--
Regards,
Tony
On 30/12/2024 11:43, John Woodgate wrote:
1.Use.TRAN analysis, not .AC,
because that doesn't show non-linearity.
2. Check that the current through
the output devices is very small with no input
signal.
On 2024-12-30 10:36, dlwarr911 via wrote:
If I build a Class B amplifier (all have cross
over distortion) What do I have to do, to see cross
over in a trace...
All I get is a perfect looking sign wave... What
would be the analysis and steps to do this...??
?
Any thoughts on this would certainly be
appreciated..... Thanks....
--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
|
Re: LM324 based automatic voltage stabilizer circuit simulation
On Mon, Dec 30, 2024 at 11:44 AM, MD MUBDIUL HASAN wrote:
?kindly share the uploaded link here.
It's in here:
?
Files > Temp
?
which is where all newly uploaded files are.
?
Andy
?
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Re: LM324 based automatic voltage stabilizer circuit simulation
Mike,
Thanks a lot, kindly share the uploaded link here.
On Monday, December 30, 2024 at 10:48:06 AM GMT+1, Mike Fraser <mrfraser@...> wrote:
Dave,
I just uploaded the file "MF_VCpot.zip".
I got tired of trying to allocate floating net names to different pots.
I chose the pin name as "PC", because it is the Pot Control pin.
Feel free to Look over the files and see if it will help with your "Fz" issue.
I think that it is easy to apply net names from the top level to subcircuits.
Mike
|
Re: Can LTspice show Cross Over distortion of a class B type amplifiers...
Yes, I know. I have already uploaded such a schematic
example using one a few years go. It doesn't explicitly show
crossover distortion, though - just the residual.
--
Regards,
Tony
On 30/12/2024 16:46, aledelaplaza via
groups.io wrote:
toggle quoted message
Show quoted text
To evaluate
and quantize crossover distortion you can use a notch filter
(RC bridge) to eliminate the fundamental frequency out of the
output voltage.
I have uploaded an example schematic
featuring the Quad 303 output stage.
--
Regards,
Tony
On 30/12/2024 11:56, Tony Casey wrote:
You can also do this with a .DC
analysis. With this it's also very easy to do a
"wingspread" plot, which plots the incremental gain, which
is very revealing.
--
Regards,
Tony
On 30/12/2024 11:43, John Woodgate wrote:
1.Use.TRAN analysis, not .AC,
because that doesn't show non-linearity.
2. Check that the current through
the output devices is very small with no input
signal.
On 2024-12-30 10:36, dlwarr911 via wrote:
If I build a Class B amplifier (all have cross
over distortion) What do I have to do, to see cross
over in a trace...
All I get is a perfect looking sign wave... What
would be the analysis and steps to do this...??
?
Any thoughts on this would certainly be
appreciated..... Thanks....
--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
|
Re: Can LTspice show Cross Over distortion of a class B type amplifiers...
To evaluate and quantize crossover distortion you can use a notch filter (RC bridge) to eliminate the fundamental frequency out of the output voltage.
I have uploaded an example
schematic featuring the Quad 303 output stage.
--
Regards,
Tony
On 30/12/2024 11:56, Tony Casey wrote:
You
can also do this with a .DC analysis. With this it's also very
easy to do a "wingspread" plot, which plots the incremental gain,
which is very revealing.
--
Regards,
Tony
On 30/12/2024 11:43, John Woodgate
wrote:
1.Use.TRAN analysis, not .AC, because that
doesn't show non-linearity.
2. Check that the current through the
output devices is very small with no input signal.
On 2024-12-30 10:36, dlwarr911 via
wrote:
If I build a Class B amplifier (all have cross over
distortion) What do I have to do, to see cross over in a
trace...
All I get is a perfect looking sign wave... What would be
the analysis and steps to do this...??
?
Any thoughts on this would certainly be appreciated.....
Thanks....
--
OOO - Own Opinions Only
Best Wishes
John Woodgate
Keep trying
|
Re: LTspice 24.1 Beta Available Now
On Mon, Dec 30, 2024 at 09:49 AM, <emilien.sabard@...> wrote:
?- MultiTabs per plot setting could be very nice, especially when we changed simulation between .ac and .tran we do not necessarily want to draw the same curves.
The best way to handle different simulations, is to name the schematics differently.? Say, MySim_Tran.asc and MySim_AC.asc, which might be identical except for their simulation commands.? Then each has its own plot settings file, and you can switch back and forth without difficulty.? Also this lets you keep both results available for later, since each .RAW file can contain one but not both simulations.
?
?- For hierarchical schemas: Option to automatically update the port between the schema (.asc) and the symbol (.sym)
What is there that you can't already do?? I am just trying to understand the thought.
?
In many cases, an automatically created symbol file from the lower-level schematic is sufficient.? Therefore, just delete the old symbol file and ;let LTspice make a new one.
?
LTspice does not use ".sym" files.? I'm assuming you meant to write ".asy".
?
Andy
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Re: LTspice 24.1 Beta Available Now
On Mon, Dec 30, 2024 at 09:49 AM, <emilien.sabard@...> wrote:
Some additionals features : Some options for future releases. Christmas is over, but it will be for next year:)
...
As you know, this group is not the place to officially make suggestions to the LTspice developers about recommendations or improvements.? This group is people like you who use LTspice; we are not its developers.? To make your recommendations known to Analog Devices, you must follow what it says under Help > About LTspice and use the EngineerZone.
?
Andy
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John Woodgate
Tony Casey