Re: Bad noise models for jfet transistors
#NOISE
I have written about this several times in this group, starting with
#138735. I
have also complained to ADI about it a number of times. All to no
avail.
It seems that the general problem with the affected models is that
the Kf parameter in standard.jft is 1e6 times bigger than the same
model available directly from Linear Systems. It looks like a
transcription error made by someone at ADI, or whoever they have
outsourced the standard libraries to.
--
Regards,
Tony
On 29/07/2023 07:05, Александр
Бордодынов wrote:
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I haven't
updated for a long time (since March 15). Now I updated and found
that Linear Systems' JFET models have been changed. From weakly
wrong noise models they replaced them with ultra-noisy models! I
have the correct noise models from this company have the suffix
_n. I customized the models to match the datasheet. I had to add
the suffix so that my correct models would not be replaced by the
wrong ones when updating, as I had already done several times.
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Re: Bad noise models for jfet transistors
#NOISE
My files are tools and one should take care of them.
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Re: Bad noise models for jfet transistors
#NOISE
I always do a backup of my stuff before updating, but I haven't updated in a long time, because wouldn't of they done it right the first time?
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Bad noise models for jfet transistors
#NOISE
I haven't updated for a long time (since March 15). Now I updated and found that Linear Systems' JFET models have been changed. From weakly wrong noise models they replaced them with ultra-noisy models! I have the correct noise models from this company have the suffix _n. I customized the models to match the datasheet. I had to add the suffix so that my correct models would not be replaced by the wrong ones when updating, as I had already done several times.
Bordodynov.
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It seams if I go with a little higher collector current the ZTX458 works just fine.
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Re: Reflected power in RF power supplies
Thank you for your information!
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Thanks for the help guys. I guess there is no through hole replacement of the BPS19 which is SMD.
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Re: Reflected power in RF power supplies
You're right; this discussion is off-topic for LTspice.
Have you considered /g/Test-Equipment-Design-Construction/
They have many RF and antenna people. I left the group, as I
don't do much in that space any more, but all members have many
skills in RF, amplifiers, transmitters, antennae, receivers,
transmission lines, ...
HTH,
Donald.
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Thanks for all replies.?This question is off topic but I do not
know any group or forum that that have such experienced and
generous users. This group is indeed a great treasure!
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Oops, sorry. Now I can't find the BPS19
either. I expect it's shy and you have frightened it away. I'm
sure I did find it. BPS19: f_t 200 MHz Vce 20 V BFS19 f_t 260
MHz? Vce 30 V.
On 2023-07-28 22:55, Tony Casey wrote:
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John wrote, "That's odd. I found several. Try:?".
No, that's the BFS19.? Richard asked about the BPS19.
My take on it is that BPS19 is ancient and BFS19 is a modern-day replacement.? Or maybe it was a typo.
Andy
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On 28 Jul 2023 23:41, John Woodgate <jmw@...> wrote:
That's odd. I found several. Try:
On 2023-07-28 22:22, Tony Casey wrote:
Do you have a datasheet for this device? Google can't find one. Or
is it possible it's the BSP19 you're interested in? Both Nexperia
and Onsemi have those, but they're not THDs.
Why don't you work with devices that are commonly available?
--
Regards,
Tony
On 28/07/2023 20:53, Richard Andrews
via groups.io wrote:
Hi all, just
looking for a model file for an equivalent through hole
transistor to the BPS19.
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i am away from my desktop. I'll get back with you soon.
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That's odd. I found several. Try:
On 2023-07-28 22:22, Tony Casey wrote:
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Do you have a datasheet for this device? Google can't find one. Or
is it possible it's the BSP19 you're interested in? Both Nexperia
and Onsemi have those, but they're not THDs.
Why don't you work with devices that are commonly available?
--
Regards,
Tony
On 28/07/2023 20:53, Richard Andrews
via groups.io wrote:
Hi all, just
looking for a model file for an equivalent through hole
transistor to the BPS19.
|
Do you have a datasheet for this device? Google can't find one. Or
is it possible it's the BSP19 you're interested in? Both Nexperia
and Onsemi have those, but they're not THDs.
Why don't you work with devices that are commonly available?
--
Regards,
Tony
On 28/07/2023 20:53, Richard Andrews
via groups.io wrote:
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Hi all, just
looking for a model file for an equivalent through hole transistor
to the BPS19.
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The BFS19 is also SMD, with somewhat 'better'
specs. But almost any small signal RF transistor with f_t around
200 MHz is probably close enough. The BF240 is available, but
the f_t seems to be different from different manufacturers.
On 2023-07-28 21:31, Andy I wrote:
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Google has trouble finding anything about the BPS19 transistor.
One source recommends the BFS19 as a replacement.? I won't vouch
for it being a replacement, so try to verify.??Note that
through-hole versus surface-mount makes no difference for SPICE
models, unless your regime is UHF or above.
Nexperia's BFS19 model is:
.MODEL BFS19 NPN (IS=2.9320E-16 NF=0.9869 ISE=1.814E-15
NE=1.411 BF=84.24 IKF=0.1702
+ VAF=130.5?NR=0.9848 ISC=3.133E-16 NC=0.9935 BR=2.933 IKR=9.000
VAR=4.860
+ RB=1 IRB=1E-06 RBM=1 RE=0.8047 RC=0.9861 XTB=0 EG=1.11 XTI=3
+ CJE=1.922E-12 VJE=0.6927 MJE=0.3045 TF=6.298E-10 XTF=113.6
VTF=5.391
+ ITF=0.4458 PTF=0 CJC=1.554E-12 VJC=0.3932 MJC=0.1891
XCJC=0.1200
+ TR=1.00E-07 CJS=0 VJS=0.75 MJS=0.333 FC=0.9333)
?
In 2003, Helmut Sennewald uploaded
this model:
.MODEL BFS19 NPN(IS=2.9320E-16 ISE=1.814E-15 ISC=3.133E-16
XTI=3
+ BF=84.24 BR=2.933 IKF=0.1702 IKR=9.000 XTB=1.5
+ VAF=130.5 VAR=4.860 VJE=0.6927 VJC=0.3932
+ RE=0.8047 RC=0.9861 RB=1 RBM=1 IRB=1E-06
+ CJE=1.922E-12 CJC=1.554E-12 XCJC=0.1200 FC=0.9333
+ NF=0.9869 NR=0.9848 NE=1.411 NC=0.9935 MJE=0.3045
MJC=0.1891
+ TF=6.298E-10 TR=1.00E-07 PTF=0 ITF=0.4458 VTF=5.391
XTF=113.6
+ EG=1.11 KF=1E-9 AF=1 MFG=PHILIPS)
Note Helmut's model was from Philips (now Nexperia), so these
two models might be identical, with the terms rearranged.? I
only checked a few of them and they looked the same.
YMMV.
Andy
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Google has trouble finding anything about the BPS19 transistor. One source recommends the BFS19 as a replacement.? I won't vouch for it being a replacement, so try to verify.??Note that through-hole versus surface-mount makes no difference for SPICE models, unless your regime is UHF or above. Nexperia's BFS19 model is:
.MODEL BFS19 NPN (IS=2.9320E-16 NF=0.9869 ISE=1.814E-15 NE=1.411 BF=84.24 IKF=0.1702
+ VAF=130.5?NR=0.9848 ISC=3.133E-16 NC=0.9935 BR=2.933 IKR=9.000 VAR=4.860
+ RB=1 IRB=1E-06 RBM=1 RE=0.8047 RC=0.9861 XTB=0 EG=1.11 XTI=3
+ CJE=1.922E-12 VJE=0.6927 MJE=0.3045 TF=6.298E-10 XTF=113.6 VTF=5.391
+ ITF=0.4458 PTF=0 CJC=1.554E-12 VJC=0.3932 MJC=0.1891 XCJC=0.1200
+ TR=1.00E-07 CJS=0 VJS=0.75 MJS=0.333 FC=0.9333)
?
In 2003, Helmut Sennewald uploaded this model:
.MODEL BFS19 NPN(IS=2.9320E-16 ISE=1.814E-15 ISC=3.133E-16 XTI=3
+ BF=84.24 BR=2.933 IKF=0.1702 IKR=9.000 XTB=1.5
+ VAF=130.5 VAR=4.860 VJE=0.6927 VJC=0.3932
+ RE=0.8047 RC=0.9861 RB=1 RBM=1 IRB=1E-06
+ CJE=1.922E-12 CJC=1.554E-12 XCJC=0.1200 FC=0.9333
+ NF=0.9869 NR=0.9848 NE=1.411 NC=0.9935 MJE=0.3045 MJC=0.1891
+ TF=6.298E-10 TR=1.00E-07 PTF=0 ITF=0.4458 VTF=5.391 XTF=113.6
+ EG=1.11 KF=1E-9 AF=1 MFG=PHILIPS) Note Helmut's model was from Philips (now Nexperia), so these two models might be identical, with the terms rearranged.? I only checked a few of them and they looked the same. YMMV.
Andy
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Hi all, just looking for a model file for an equivalent through hole transistor to the BPS19.
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Re: Multi-cycle current control
Thanks, Ron, but MCC is what the industry
uses; I don't have an opportunity to change that. I'm sure they
looked at 'magic sine waves'.
On 2023-07-28 17:01, ron davison wrote:
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If your trying to reduce harmonics and edge rate
generated frequencies, would not the EMI be reduced iff
switching the max current only after having the meduim current
on before an on event or off to on for an off event of max
current source. You can aproximate a sine wave as best as
pssoible with the sequence?
Low, mis, mid?+ low, high, high?+ low, high?+ mid, high?+
mid?+ low. then reverse ands tep down to complet 1st 1/2 wave.
Then repeat for negtive AC half cycle input.
This would give the lowest EMI. If this was set as
aproximate load point, then any fine temp adjustments would
not add to much surge currents.
On Fri, Jul 28, 2023 at
4:25?AM John Woodgate < jmw@...>
wrote:
I uploaded a graph to Photos.The graph
shows the current and voltage waveforms for an example
of 3-cycle control, typically used for supplying heaters
that need fine temperature control. I want to generate
that current waveform in LTspice to look at its
spectrum.
I need help to specify the current
waveform, presumably as a BI source. All assistance
gratefully acknowledged.
--
Ron Davison
principle
Efficient
Electronic Solutions
760.505.4380
“What
I cannot build, I do not understand”?Richard
Feynman?
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Re: Multi-cycle current control
If your trying to reduce harmonics and edge rate generated frequencies, would not the EMI be reduced iff switching the max current only after having the meduim current on before an on event or off to on for an off event of max current source. You can aproximate a sine wave as best as pssoible with the sequence? Low, mis, mid?+ low, high, high?+ low, high?+ mid, high?+ mid?+ low. then reverse ands tep down to complet 1st 1/2 wave. Then repeat for negtive AC half cycle input. This would give the lowest EMI. If this was set as aproximate load point, then any fine temp adjustments would not add to much surge currents.
On Fri, Jul 28, 2023 at 4:25?AM John Woodgate < jmw@...> wrote:
I uploaded a graph to Photos.The graph shows
the current and voltage waveforms for an example of 3-cycle
control, typically used for supplying heaters that need fine
temperature control. I want to generate that current waveform in
LTspice to look at its spectrum.
I need help to specify the current waveform,
presumably as a BI source. All assistance gratefully
acknowledged.
-- Ron Davison principle Efficient Electronic Solutions 760.505.4380
“What I cannot build, I do not understand”?Richard Feynman?
|
Re: Multi-cycle current control
You are right; It's 3.33 Hz. I didn't have
grid lines enabled. Your Waveform settings are very different
from mine, but I can cope.
On 2023-07-28 15:58, Andy I wrote:
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5 Hz?? Where does that come from?
The requested waveform repeats every 0.06 ms --> 16.67 Hz.? Is
there something that happens beyond the 0.12 s window you showed
us?
LTspice's FFT shows me a component at 3.33 Hz but it's about 80 dB
below the fundamental.? I saw nothing at 5 Hz.
Andy
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Tony Casey
John Woodgate