Discussion:
fast NPN in LT Spice
(too old to reply)
john larkin
2024-06-02 22:36:35 UTC
Permalink
There are many NPNs in the standard LT Spice library.

Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.

I want to make a model of the MC10EP89 gate.
Cursitor Doom
2024-06-02 22:45:17 UTC
Permalink
Post by john larkin
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell from
the jillion lines of fine-print parameters.
I want to make a model of the MC10EP89 gate.
Define "fast".
john larkin
2024-06-02 23:28:43 UTC
Permalink
On Sun, 2 Jun 2024 22:45:17 -0000 (UTC), Cursitor Doom
Post by Cursitor Doom
Post by john larkin
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell from
the jillion lines of fine-print parameters.
I want to make a model of the MC10EP89 gate.
Define "fast".
2 GHz or so. Something that works inside the 10EP89.

2SC3838K looks OK.
Edward Rawde
2024-06-02 23:46:14 UTC
Permalink
Post by john larkin
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
Post by john larkin
I want to make a model of the MC10EP89 gate.
john larkin
2024-06-03 00:17:48 UTC
Permalink
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
Post by john larkin
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.

2SC3838K looks OK.

It's hard to pick parts, discrete or ICs, from the library.
Edward Rawde
2024-06-03 00:23:53 UTC
Permalink
Post by john larkin
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
Post by john larkin
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It isn't but models are easy to find, make sure the link I posted includes the end quote.

I've never done any ECL modeling but
https://www.google.com/search?q=AN1560+spice
looks useful if I wanted to do so.
Post by john larkin
It's hard to pick parts, discrete or ICs, from the library.
Edward Rawde
2024-06-03 00:35:02 UTC
Permalink
Post by john larkin
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
Post by john larkin
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
Yes it would be nice if a description of the part as well as the part number could be included.
john larkin
2024-06-03 03:22:57 UTC
Permalink
On Sun, 2 Jun 2024 20:35:02 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
Post by john larkin
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
Yes it would be nice if a description of the part as well as the part number could be included.
A sortable column of Ft would be nice for transistors. Lacking that,
sorting on Vce helps spot the RF parts. Low voltage suggests RF.
Bill Sloman
2024-06-03 07:18:15 UTC
Permalink
Post by john larkin
On Sun, 2 Jun 2024 20:35:02 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
Post by john larkin
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
Yes it would be nice if a description of the part as well as the part number could be included.
A sortable column of Ft would be nice for transistors. Lacking that,
sorting on Vce helps spot the RF parts. Low voltage suggests RF.
Here's a circuit that includes a 5GHz ft BFR92A, which a typical
broad-band transistor. I had to put in the Spice model into the .asc
file myself.
There used to be quite a few of them around, but - as Phil Hobbs has
mentioned - most of them have gone obsolete. He has tracked down a
surviving PNP equivalent, but you won't need that to simulate ECL.

It's not the first time I've posted such a .asc file here.

Version 4
SHEET 1 2924 1040
WIRE 128 -720 -768 -720
WIRE 304 -720 128 -720
WIRE 656 -720 304 -720
WIRE 1088 -720 656 -720
WIRE 1376 -720 1088 -720
WIRE 1584 -720 1376 -720
WIRE 1088 -576 1088 -720
WIRE 1376 -576 1376 -720
WIRE 128 -560 128 -720
WIRE 304 -560 304 -720
WIRE 656 -560 656 -720
WIRE 1584 -544 1584 -720
WIRE 1088 -400 1088 -496
WIRE 1088 -400 960 -400
WIRE 1248 -400 1088 -400
WIRE 960 -368 960 -400
WIRE 1248 -352 1248 -400
WIRE 656 -320 656 -480
WIRE 896 -320 656 -320
WIRE 1376 -304 1376 -496
WIRE 1376 -304 1312 -304
WIRE 128 -288 128 -480
WIRE 176 -288 128 -288
WIRE 304 -288 304 -480
WIRE 304 -288 240 -288
WIRE 656 -208 656 -320
WIRE 1376 -192 1376 -304
WIRE 1584 -192 1584 -480
WIRE 1584 -192 1376 -192
WIRE 304 -160 304 -288
WIRE 448 -160 304 -160
WIRE 592 -160 448 -160
WIRE -768 -64 -768 -720
WIRE 128 48 128 -288
WIRE 1376 48 1376 -192
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WIRE 64 96 -192 96
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WIRE 448 176 448 -160
WIRE -432 240 -432 96
WIRE -768 416 -768 16
WIRE -768 416 -880 416
WIRE -736 416 -768 416
WIRE -432 416 -432 320
WIRE -432 416 -736 416
WIRE 304 416 304 240
WIRE 304 416 -432 416
WIRE 960 416 960 -272
WIRE 960 416 304 416
WIRE 1376 416 1376 128
WIRE 1376 416 960 416
WIRE 1424 416 1376 416
WIRE 1520 416 1424 416
WIRE 128 464 128 144
WIRE 656 464 656 -112
WIRE 656 464 128 464
WIRE 1424 480 1424 416
WIRE -880 496 -880 416
WIRE 656 496 656 464
WIRE 1248 624 1248 -256
WIRE 1296 624 1248 624
WIRE 1424 624 1424 560
WIRE 1424 624 1296 624
WIRE -736 640 -736 416
WIRE -736 656 -736 640
WIRE 1424 688 1424 624
WIRE -736 944 -736 720
WIRE 448 944 448 256
WIRE 448 944 -736 944
WIRE 656 944 656 576
WIRE 656 944 448 944
WIRE 1424 944 1424 768
WIRE 1424 944 656 944
WIRE 1648 944 1424 944
FLAG -880 496 0
FLAG 1296 624 out
SYMBOL npn 64 48 R0
SYMATTR InstName Q1
SYMATTR Value BFR92A
SYMBOL npn 592 -208 R0
SYMATTR InstName Q2
SYMATTR Value BFR92A
SYMBOL voltage -768 -80 R0
WINDOW 123 0 0 Left 0
WINDOW 39 24 44 Left 2
SYMATTR SpiceLine Rser=0.1
SYMATTR InstName V1
SYMATTR Value 15.0
SYMBOL voltage -736 624 R0
WINDOW 123 0 0 Left 0
WINDOW 39 24 44 Left 2
SYMATTR SpiceLine Rser=0.1
SYMATTR InstName V2
SYMATTR Value 15.0
SYMBOL voltage -432 224 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V3
SYMATTR Value PULSE(0 .2 1n 300p 300p 100p 100n 2)
SYMBOL res -176 80 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 27
SYMBOL res 640 480 R0
SYMATTR InstName R3
SYMATTR Value 3k0
SYMBOL res 112 -576 R0
SYMATTR InstName R4
SYMATTR Value 2k
SYMBOL res 288 144 R0
SYMATTR InstName R5
SYMATTR Value 100
SYMBOL res 640 -576 R0
SYMATTR InstName R6
SYMATTR Value 1k
SYMBOL res 288 -576 R0
SYMATTR InstName R2
SYMATTR Value 5k
SYMBOL cap 240 -304 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C1
SYMATTR Value 10p
SYMBOL res 432 160 R0
SYMATTR InstName R7
SYMATTR Value 7k5
SYMBOL pnp 1312 -256 R180
SYMATTR InstName Q3
SYMATTR Value 2N3906
SYMBOL pnp 896 -272 M180
SYMATTR InstName Q4
SYMATTR Value 2N3906
SYMBOL res 1072 -592 R0
SYMATTR InstName R8
SYMATTR Value 100
SYMBOL res 1360 -592 R0
SYMATTR InstName R9
SYMATTR Value 3k3
SYMBOL res 1360 32 R0
SYMATTR InstName R10
SYMATTR Value 12k
SYMBOL res 1408 464 R0
SYMATTR InstName R11
SYMATTR Value 56
SYMBOL res 1408 672 R0
SYMATTR InstName R12
SYMATTR Value 360
SYMBOL cap 1568 -544 R0
SYMATTR InstName C2
SYMATTR Value 10n
TEXT -272 1000 Left 2 !.model BFR92A NPN(IS=0.1213E-15 VAF=30 BF=94.73
IKF=0.46227 XTB=0 BR=10.729 CJC=946.47E-15 CJE=10.416E-15 TR=1.2744E-9
TF=26.796E-12 ITF=0.0044601 VTF=0.32861 XTF=0.3817 RB=14.998
RC=0.13793 RE=0.29088 Vceo=15 Icrating=4m mfg=Infineon)
TEXT -904 1024 Left 2 !.tran 0 300n 0
--
Bill Sloman, Sydney
john larkin
2024-06-03 13:59:23 UTC
Permalink
Post by Bill Sloman
Post by john larkin
On Sun, 2 Jun 2024 20:35:02 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
Post by john larkin
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
Yes it would be nice if a description of the part as well as the part number could be included.
A sortable column of Ft would be nice for transistors. Lacking that,
sorting on Vce helps spot the RF parts. Low voltage suggests RF.
Here's a circuit that includes a 5GHz ft BFR92A, which a typical
broad-band transistor. I had to put in the Spice model into the .asc
file myself.
There used to be quite a few of them around, but - as Phil Hobbs has
mentioned - most of them have gone obsolete. He has tracked down a
surviving PNP equivalent, but you won't need that to simulate ECL.
It's not the first time I've posted such a .asc file here.
Gosh, what a hideous mess, in many respects.
Post by Bill Sloman
Version 4
SHEET 1 2924 1040
WIRE 128 -720 -768 -720
WIRE 304 -720 128 -720
WIRE 656 -720 304 -720
WIRE 1088 -720 656 -720
WIRE 1376 -720 1088 -720
WIRE 1584 -720 1376 -720
WIRE 1088 -576 1088 -720
WIRE 1376 -576 1376 -720
WIRE 128 -560 128 -720
WIRE 304 -560 304 -720
WIRE 656 -560 656 -720
WIRE 1584 -544 1584 -720
WIRE 1088 -400 1088 -496
WIRE 1088 -400 960 -400
WIRE 1248 -400 1088 -400
WIRE 960 -368 960 -400
WIRE 1248 -352 1248 -400
WIRE 656 -320 656 -480
WIRE 896 -320 656 -320
WIRE 1376 -304 1376 -496
WIRE 1376 -304 1312 -304
WIRE 128 -288 128 -480
WIRE 176 -288 128 -288
WIRE 304 -288 304 -480
WIRE 304 -288 240 -288
WIRE 656 -208 656 -320
WIRE 1376 -192 1376 -304
WIRE 1584 -192 1584 -480
WIRE 1584 -192 1376 -192
WIRE 304 -160 304 -288
WIRE 448 -160 304 -160
WIRE 592 -160 448 -160
WIRE -768 -64 -768 -720
WIRE 128 48 128 -288
WIRE 1376 48 1376 -192
WIRE -272 96 -432 96
WIRE 64 96 -192 96
WIRE 304 160 304 -160
WIRE 448 176 448 -160
WIRE -432 240 -432 96
WIRE -768 416 -768 16
WIRE -768 416 -880 416
WIRE -736 416 -768 416
WIRE -432 416 -432 320
WIRE -432 416 -736 416
WIRE 304 416 304 240
WIRE 304 416 -432 416
WIRE 960 416 960 -272
WIRE 960 416 304 416
WIRE 1376 416 1376 128
WIRE 1376 416 960 416
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WIRE 1520 416 1424 416
WIRE 128 464 128 144
WIRE 656 464 656 -112
WIRE 656 464 128 464
WIRE 1424 480 1424 416
WIRE -880 496 -880 416
WIRE 656 496 656 464
WIRE 1248 624 1248 -256
WIRE 1296 624 1248 624
WIRE 1424 624 1424 560
WIRE 1424 624 1296 624
WIRE -736 640 -736 416
WIRE -736 656 -736 640
WIRE 1424 688 1424 624
WIRE -736 944 -736 720
WIRE 448 944 448 256
WIRE 448 944 -736 944
WIRE 656 944 656 576
WIRE 656 944 448 944
WIRE 1424 944 1424 768
WIRE 1424 944 656 944
WIRE 1648 944 1424 944
FLAG -880 496 0
FLAG 1296 624 out
SYMBOL npn 64 48 R0
SYMATTR InstName Q1
SYMATTR Value BFR92A
SYMBOL npn 592 -208 R0
SYMATTR InstName Q2
SYMATTR Value BFR92A
SYMBOL voltage -768 -80 R0
WINDOW 123 0 0 Left 0
WINDOW 39 24 44 Left 2
SYMATTR SpiceLine Rser=0.1
SYMATTR InstName V1
SYMATTR Value 15.0
SYMBOL voltage -736 624 R0
WINDOW 123 0 0 Left 0
WINDOW 39 24 44 Left 2
SYMATTR SpiceLine Rser=0.1
SYMATTR InstName V2
SYMATTR Value 15.0
SYMBOL voltage -432 224 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V3
SYMATTR Value PULSE(0 .2 1n 300p 300p 100p 100n 2)
SYMBOL res -176 80 R90
WINDOW 0 0 56 VBottom 2
WINDOW 3 32 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 27
SYMBOL res 640 480 R0
SYMATTR InstName R3
SYMATTR Value 3k0
SYMBOL res 112 -576 R0
SYMATTR InstName R4
SYMATTR Value 2k
SYMBOL res 288 144 R0
SYMATTR InstName R5
SYMATTR Value 100
SYMBOL res 640 -576 R0
SYMATTR InstName R6
SYMATTR Value 1k
SYMBOL res 288 -576 R0
SYMATTR InstName R2
SYMATTR Value 5k
SYMBOL cap 240 -304 R90
WINDOW 0 0 32 VBottom 2
WINDOW 3 32 32 VTop 2
SYMATTR InstName C1
SYMATTR Value 10p
SYMBOL res 432 160 R0
SYMATTR InstName R7
SYMATTR Value 7k5
SYMBOL pnp 1312 -256 R180
SYMATTR InstName Q3
SYMATTR Value 2N3906
SYMBOL pnp 896 -272 M180
SYMATTR InstName Q4
SYMATTR Value 2N3906
SYMBOL res 1072 -592 R0
SYMATTR InstName R8
SYMATTR Value 100
SYMBOL res 1360 -592 R0
SYMATTR InstName R9
SYMATTR Value 3k3
SYMBOL res 1360 32 R0
SYMATTR InstName R10
SYMATTR Value 12k
SYMBOL res 1408 464 R0
SYMATTR InstName R11
SYMATTR Value 56
SYMBOL res 1408 672 R0
SYMATTR InstName R12
SYMATTR Value 360
SYMBOL cap 1568 -544 R0
SYMATTR InstName C2
SYMATTR Value 10n
TEXT -272 1000 Left 2 !.model BFR92A NPN(IS=0.1213E-15 VAF=30 BF=94.73
IKF=0.46227 XTB=0 BR=10.729 CJC=946.47E-15 CJE=10.416E-15 TR=1.2744E-9
TF=26.796E-12 ITF=0.0044601 VTF=0.32861 XTF=0.3817 RB=14.998
RC=0.13793 RE=0.29088 Vceo=15 Icrating=4m mfg=Infineon)
TEXT -904 1024 Left 2 !.tran 0 300n 0
Bill Sloman
2024-06-03 14:10:32 UTC
Permalink
Post by john larkin
Post by Bill Sloman
Post by john larkin
On Sun, 2 Jun 2024 20:35:02 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
Post by john larkin
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
Yes it would be nice if a description of the part as well as the part number could be included.
A sortable column of Ft would be nice for transistors. Lacking that,
sorting on Vce helps spot the RF parts. Low voltage suggests RF.
Here's a circuit that includes a 5GHz ft BFR92A, which a typical
broad-band transistor. I had to put in the Spice model into the .asc
file myself.
There used to be quite a few of them around, but - as Phil Hobbs has
mentioned - most of them have gone obsolete. He has tracked down a
surviving PNP equivalent, but you won't need that to simulate ECL.
It's not the first time I've posted such a .asc file here.
Gosh, what a hideous mess, in many respects.
Do tell us why. You do claim to revel in electronic discussion.
--
Bill Sloman, Sydney
legg
2024-06-06 03:46:24 UTC
Permalink
On Tue, 4 Jun 2024 00:10:32 +1000, Bill Sloman <***@ieee.org>
wrote:
<snip>
Post by Bill Sloman
Post by john larkin
Gosh, what a hideous mess, in many respects.
Do tell us why. You do claim to revel in electronic discussion.
Perhaps its the nonlinearity of the output stage, which is biased off.

So it's a switch, but the slow speed of the output, if engaged,
results in a stretched pulse.

The assertion that spice parameter Tf is related to spec sheet Ft is
only a guess.

The bfr92a model written into your simulation turns out to
be part of a more complete model published as a die-within-a-package.
There's little difference in performance when substituted into the
simulation.

If all the models with Tf<20ps are evaluated, you get unpredictable
results. Note that the bfr92a model doesn't actually meet this
limitation, but other similar models do (~bfr93). There are roughly
270 of them.

Each will either:

- fail to engage with the slow output detector.(31)
- act roughly like the original simulation.(217)
- oscillate at an unrelated frequency.(19)
- stall.(1)
- give incoherent wild results (2)

http://ve3ute.ca/query/Tf_20ps_vs_bfr92a.zip

Just why one model does one thing, while another does something
else might be interesting to figure out.

RL
Bill Sloman
2024-06-06 13:18:12 UTC
Permalink
Post by legg
<snip>
Post by Bill Sloman
Post by john larkin
Gosh, what a hideous mess, in many respects.
Do tell us why. You do claim to revel in electronic discussion.
Perhaps its the nonlinearity of the output stage, which is biased off.
So it's a switch, but the slow speed of the output, if engaged,
results in a stretched pulse.
The pulse stretching happens between the two BFR92 transistors, which
act as a classical emitted-coupled monostable, which stretch the input
spike out to about 30nsec

Q3 and Q4 just level shift this down to provide an ECL-level output
pulse which is also 30nsec wide.

There are other ways of doing this kind of level shifting and you can
use faster transistors.
Post by legg
The assertion that spice parameter Tf is related to spec sheet Ft is
only a guess.
Not one that I made. The BFR92a is just the default broad-band
transistor, which is why Jeroen Belleman picked it too.
Post by legg
The bfr92a model written into your simulation turns out to
be part of a more complete model published as a die-within-a-package.
There's little difference in performance when substituted into the
simulation.
If all the models with Tf<20ps are evaluated, you get unpredictable
results. Note that the bfr92a model doesn't actually meet this
limitation, but other similar models do (~bfr93). There are roughly
270 of them.
- fail to engage with the slow output detector.(31)
If they aren't fast enough to get triggered as emitter-coupled
monostable by a pulse that is 400psec wide at hallf-maximium voltage
of 100mV.
Post by legg
- act roughly like the original simulation.(217)
- oscillate at an unrelated frequency.(19)
Broad-band transistors will oscillate without a base-stopper of adequate
resistance - I tended to end up with resistors between 22R and 33R.
There are better solutions, but in the work I did it wasn't worth the
trouble of finding them.
Post by legg
- stall.(1)
Up the gain.
Post by legg
- give incoherent wild results (2)
Change the base-stopper resistance.
Post by legg
http://ve3ute.ca/query/Tf_20ps_vs_bfr92a.zip
Just why one model does one thing, while another does something
else might be interesting to figure out.
No model is perfect. If you model something and it seems to work, it's
worth putting together a real circuit (which takes longer) and seeing
what it actually does.

If it doesn't work, or doesn't work all that well. fiddling with the
model may point the way to something that might work better.
--
Bill Sloman, Sydney
--
This email has been checked for viruses by Norton antivirus software.
www.norton.com
legg
2024-06-06 18:05:24 UTC
Permalink
<snip>
Post by Bill Sloman
Post by legg
If all the models with Tf<20ps are evaluated, you get unpredictable
results. Note that the bfr92a model doesn't actually meet this
limitation, but other similar models do (~bfr93). There are roughly
270 of them.
- fail to engage with the slow output detector.(31)
If they aren't fast enough to get triggered as emitter-coupled
monostable by a pulse that is 400psec wide at hallf-maximium voltage
of 100mV.
Post by legg
- act roughly like the original simulation.(217)
- oscillate at an unrelated frequency.(19)
Broad-band transistors will oscillate without a base-stopper of adequate
resistance - I tended to end up with resistors between 22R and 33R.
There are better solutions, but in the work I did it wasn't worth the
trouble of finding them.
Post by legg
- stall.(1)
Up the gain.
Post by legg
- give incoherent wild results (2)
Change the base-stopper resistance.
Post by legg
http://ve3ute.ca/query/Tf_20ps_vs_bfr92a.zip
Just why one model does one thing, while another does something
else might be interesting to figure out.
No model is perfect. If you model something and it seems to work, it's
worth putting together a real circuit (which takes longer) and seeing
what it actually does.
If it doesn't work, or doesn't work all that well. fiddling with the
model may point the way to something that might work better.
--
Bill Sloman, Sydney
It's difficult to isolate a model parameter or product of parameters
that predict the performance demonstrated in this simulation.

Oscillators seem to have ( ~ mostly) high Rbb, which is
device-specific. . . . but also lower ( 1/100) IKR, which you'd
think was irrelevant.

Bf, Tr, Tf and capacitances don't stand out.

I suppose you'd need to look at the numbers separating astable from
monostable operation. You wouldn't want an unspecified component
characteric to dominate basic circuit function.

RL
Bill Sloman
2024-06-07 04:03:16 UTC
Permalink
<snip>
Post by legg
It's difficult to isolate a model parameter or product of parameters
that predict the performance demonstrated in this simulation.
Oscillators seem to have ( ~ mostly) high Rbb, which is
device-specific. . . . but also lower ( 1/100) IKR, which you'd
think was irrelevant.
Bf, Tr, Tf and capacitances don't stand out.
I suppose you'd need to look at the numbers separating astable from
monostable operation. You wouldn't want an unspecified component
characteric to dominate basic circuit function.
You don't get the choice, unless you are in the position of developing a
new transistor for a new market.

Most of us are in the position of finding a transistor which we can buy
- preferably off the shelf - which we can use to do a specific job.

The options tend to be pretty restricted. There are a lot fewer
broad-band transistors on the market than there used to be.

The manufacturer's Spice model give us the option of modelling a circuit
which might work in some version of Spice, and tweaking the circuit to
get the simulation to perform our job tolerably well.

We can't sell the simulation - customers want real circuits that work in
real life.
--
Bill Sloman, Sydney
--
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legg
2024-06-07 13:24:10 UTC
Permalink
Post by legg
<snip>
Post by legg
It's difficult to isolate a model parameter or product of parameters
that predict the performance demonstrated in this simulation.
Oscillators seem to have ( ~ mostly) high Rbb, which is
device-specific. . . . but also lower ( 1/100) IKR, which you'd
think was irrelevant.
Bf, Tr, Tf and capacitances don't stand out.
I suppose you'd need to look at the numbers separating astable from
monostable operation. You wouldn't want an unspecified component
characteric to dominate basic circuit function.
You don't get the choice, unless you are in the position of developing a
new transistor for a new market.
Most of us are in the position of finding a transistor which we can buy
- preferably off the shelf - which we can use to do a specific job.
The options tend to be pretty restricted. There are a lot fewer
broad-band transistors on the market than there used to be.
The manufacturer's Spice model give us the option of modelling a circuit
which might work in some version of Spice, and tweaking the circuit to
get the simulation to perform our job tolerably well.
We can't sell the simulation - customers want real circuits that work in
real life.
--
Bill Sloman, Sydney
That's sort of what I'm talking about. You choose a part, you choose a
model, you choose a parameter that allows a model to simulate
performance more accurately. You choose a circuit configuration
with component values.

From the larger spreadsheet, you see models for 'similar devices
varying widely in performance in a particular circuit configuration.

So what is it, in the model, or in the circuit configuration, that
allows such a wide variation in performance. What parameter is a
true predictor? What weakness in the circuit is the wild card?

Looking for understanding or beneficial increase in knowledge here.
Not pushing or pulling the benefits or disadvantages of modeling
or breadboarding - already have pretty fixed opinions about that.

RL
Bill Sloman
2024-06-07 17:29:11 UTC
Permalink
<snip>
Post by legg
That's sort of what I'm talking about. You choose a part, you choose a
model, you choose a parameter that allows a model to simulate
performance more accurately. You choose a circuit configuration
with component values.
You mostly can't chose an EBIC model because the manufacturers treat
them as "commercial in confidence".

Gummel-Poon isn't as good, but it's mostly adequate.
Post by legg
From the larger spreadsheet, you see models for 'similar devices
varying widely in performance in a particular circuit configuration.
So what is it, in the model, or in the circuit configuration, that
allows such a wide variation in performance. What parameter is a
true predictor? What weakness in the circuit is the wild card?
Silly question. Gummel-Poon doesn't model inverted bipolar transistor
operation particularly well, but if you want anything else you will have
measure the device parameters for yourself, and nobody here has ever
claimed to have done that.
Post by legg
Looking for understanding or beneficial increase in knowledge here.
Not pushing or pulling the benefits or disadvantages of modeling
or breadboarding - already have pretty fixed opinions about that.
Do try to understand what practical circuit designers actually do.

I've never seen anybody set up a "spreadsheet" of transistor models.

The process is mostly working out what you can do with what you can get.

The models aren't perfect, and individual devices aren't identical, so
coping with production variation is part of the job. Some parts are
sorted by the manufacturer after production, which gives you
funny-looking parameter distributions.
--
Bill Sloman, Sydney
--
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legg
2024-06-07 21:58:26 UTC
Permalink
Post by legg
<snip>
Post by legg
That's sort of what I'm talking about. You choose a part, you choose a
model, you choose a parameter that allows a model to simulate
performance more accurately. You choose a circuit configuration
with component values.
You mostly can't chose an EBIC model because the manufacturers treat
them as "commercial in confidence".
Gummel-Poon isn't as good, but it's mostly adequate.
Post by legg
From the larger spreadsheet, you see models for 'similar devices
varying widely in performance in a particular circuit configuration.
So what is it, in the model, or in the circuit configuration, that
allows such a wide variation in performance. What parameter is a
true predictor? What weakness in the circuit is the wild card?
Silly question. Gummel-Poon doesn't model inverted bipolar transistor
operation particularly well, but if you want anything else you will have
measure the device parameters for yourself, and nobody here has ever
claimed to have done that.
Post by legg
Looking for understanding or beneficial increase in knowledge here.
Not pushing or pulling the benefits or disadvantages of modeling
or breadboarding - already have pretty fixed opinions about that.
Do try to understand what practical circuit designers actually do.
I've never seen anybody set up a "spreadsheet" of transistor models.
http://ve3ute.ca/query/bjt_spice_parameter.zip

This was compiled to keep track of models floating around in
the LTSpice community. Names were assigned that could be
related to a source.

Some obvious typos showed up, duplicates and variations,
derivatives, dated precursors etc.

Depth of parameter assignment, redundant default listings and
misinterpreted 'intended to default' values also became apparent.

Some attempt at performance over temperature also shows up in the
listing.
Post by legg
The process is mostly working out what you can do with what you can get.
The models aren't perfect, and individual devices aren't identical, so
coping with production variation is part of the job. Some parts are
sorted by the manufacturer after production, which gives you
funny-looking parameter distributions.
--
Bill Sloman, Sydney
I don't think that perfection is attempted; more representation of
performance in known physical circuitry or test measurement setups.
Test circuitry is sometimes illustrated in, or accompanies the
published specification for, the physical product.

The performance in the simulation in question doesn't touch inverted
operation, that I can see, but linear operation and ~saturated
switching may be. It's not an AC analysis.

RL
legg
2024-06-10 21:27:59 UTC
Permalink
Post by legg
<snip>
Post by legg
That's sort of what I'm talking about. You choose a part, you choose a
model, you choose a parameter that allows a model to simulate
performance more accurately. You choose a circuit configuration
with component values.
You mostly can't chose an EBIC model because the manufacturers treat
them as "commercial in confidence".
Gummel-Poon isn't as good, but it's mostly adequate.
Post by legg
From the larger spreadsheet, you see models for 'similar devices
varying widely in performance in a particular circuit configuration.
So what is it, in the model, or in the circuit configuration, that
allows such a wide variation in performance. What parameter is a
true predictor? What weakness in the circuit is the wild card?
Silly question. Gummel-Poon doesn't model inverted bipolar transistor
operation particularly well, but if you want anything else you will have
measure the device parameters for yourself, and nobody here has ever
claimed to have done that.
Post by legg
Looking for understanding or beneficial increase in knowledge here.
Not pushing or pulling the benefits or disadvantages of modeling
or breadboarding - already have pretty fixed opinions about that.
Do try to understand what practical circuit designers actually do.
I've never seen anybody set up a "spreadsheet" of transistor models.
The process is mostly working out what you can do with what you can get.
The models aren't perfect, and individual devices aren't identical, so
coping with production variation is part of the job. Some parts are
sorted by the manufacturer after production, which gives you
funny-looking parameter distributions.
--
Bill Sloman, Sydney
Right, I see Q2 normally inverted.

C2 seems unneccessarily loaded.

RL
Bill Sloman
2024-06-11 14:35:59 UTC
Permalink
<snip>
Post by legg
Right, I see Q2 normally inverted.
C2 seems unneccessarily loaded.
If you are talking about the .asc file I posted on the 3rd June, Q2
isn't "normally inverted" - its mostly on, and it gets turned off for
the 30nsec in which the stretched pulse is being generated. Inverted
operation of a bipolar transistor is usually taken to mean running
current through them in the opposite direction than is seen in normal
operation.

C2 isn't carrying any current worth worrying about. It stabilises the
voltage at the base of Q3 against the base current drawn when the output
pulse is turned on and turned off, -6.7mA when it is turned on an +2mA
when it is turned off, and holds the voltage excursion down to 3.7mV,
not that I ever bothered working this out.

If you want to discuss when the circuit does and how it does it, feel
free, but this wasn't a good start.
--
Bill Sloman, Sydney
--
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legg
2024-06-11 15:27:20 UTC
Permalink
Post by legg
<snip>
Post by legg
Right, I see Q2 normally inverted.
C2 seems unneccessarily loaded.
If you are talking about the .asc file I posted on the 3rd June, Q2
isn't "normally inverted" - its mostly on, and it gets turned off for
the 30nsec in which the stretched pulse is being generated. Inverted
operation of a bipolar transistor is usually taken to mean running
current through them in the opposite direction than is seen in normal
operation.
Just returning to this, trying to see what determines the switch from
non-switching to astable operation (ECLTN0E - ECLTN0D). Misreading a
current and voltage waveform with similar color coding.
Post by legg
C2 isn't carrying any current worth worrying about. It stabilises the
voltage at the base of Q3 against the base current drawn when the output
pulse is turned on and turned off, -6.7mA when it is turned on an +2mA
when it is turned off, and holds the voltage excursion down to 3.7mV,
not that I ever bothered working this out.
If you want to discuss when the circuit does and how it does it, feel
free, but this wasn't a good start.
--
Bill Sloman, Sydney
Not so much interested in the circuit, as its reaction to model
parameters presented by similar devices.

Not Beta, Tr or Tf in this case.

RL
Bill Sloman
2024-06-12 06:30:02 UTC
Permalink
<snip>
Post by legg
Post by Bill Sloman
Post by legg
Right, I see Q2 normally inverted.
C2 seems unneccessarily loaded.
If you are talking about the .asc file I posted on the 3rd June, Q2
isn't "normally inverted" - its mostly on, and it gets turned off for
the 30nsec in which the stretched pulse is being generated. Inverted
operation of a bipolar transistor is usually taken to mean running
current through them in the opposite direction than is seen in normal
operation.
Just returning to this, trying to see what determines the switch from
non-switching to astable operation (ECLTN0E - ECLTN0D). Misreading a
current and voltage waveform with similar color coding.
Post by Bill Sloman
C2 isn't carrying any current worth worrying about. It stabilises the
voltage at the base of Q3 against the base current drawn when the output
pulse is turned on and turned off, -6.7mA when it is turned on an +2mA
when it is turned off, and holds the voltage excursion down to 3.7mV,
not that I ever bothered working this out.
If you want to discuss when the circuit does and how it does it, feel
free, but this wasn't a good start.
Not so much interested in the circuit, as its reaction to model
parameters presented by similar devices.
You need to work out how the emitter-couple monostable works.


https://www.daenotes.com/electronics/digital-electronics/monostable-multivibrators-working-construction-types

actually does try to spell this out (in it's second section on
emitter-coupled monstables) . It doesn't do it well, but it does it well
enough that you should be able to work out what is going on, and keep
track of the base-emitter voltages across both transistors and their
effect on the collector current.

The Gummel-Poon transistor model keeeps track of the various currents
flowing in and out of each transistor junction while this is going on,
and subtle differences in the parameter values can give you different
currents (and different trajectories)
Post by legg
Not Beta, Tr or Tf in this case.
If you don't know what the circuit is doing, speculation about what the
model might be doing it is a bit pointless.

The emitter-coupled monstable isn't well understood here.

This is from the end of a long thread in 2013.

On Mar 9,
Post by legg
On Fri, 08 Mar 2013 01:18:53 -0600,
Post by Bill Sloman
On Thu, 07 Mar 2013 16:02:49 -0800, John Larkin
Post by legg
http://www.highlandtechnology.com/DSS/T240DS.shtml
---
That's not a pulse stretcher, cheater, that's a puls_generator_.
It's a one-shot. It has no internal trigger. It generates no pulses.
And neither you nor Jim have a clue as to how this might be done.
We have a customer who wants us to take this down to 10 ps
pulses. At that point, I'm not sure that I know how that might be done.
We're thinking about it.

http://books.google.co.nz/books?id=3D-pi4vP6xMOQC&pg=3DPA571&lpg=3DPA571&dq=
=3D%22emitter-coupled%22+monostable&source=3Dbl&ots=3DCFsGlVE2YN&sig=3DTUbj=
QhyQPk_cd5tj_UKlIhFVXt8&hl=3Den&sa=3DX&ei=3DTZw6UYmmPMeNyAHA4oHYAg&ved=3D0C=
EIQ6AEwAw#v=3Donepage&q=3D%22emitter-coupled%22%20monostable&f=3Dfalse

describes the emitter-coupled monostable. Put one together out of a
pair of wide-band transistors - BFR92 or better - with 33R up against
each base, and you can certainly get below 10nsec. Since the mechanism
depends on the change of base-emitter impedance with emitter current,
it isn't as easy as it might be to get a wide range of output pulse
widths.

Jim Thompson could probably remember a better solution for you. The
long-obsolete MC10198 ECL monostable

http://www.digchip.com/datasheets/parts/datasheet/343/MC10198-pdf.php

could just get down to 10nsec, but we used two of them when we wanted
to offer long pulses as well - being able to switch in bigger
capacitors put too much stray capacitance on the relevant input pin
for 10nsec operation.

Something boringly obvious with a constant current ramp and a fast
comparator would do the job, but - as with the MC10198, being able to
switch in bigger capacitors to generate much longer pulses is probably
incompatible with a 10nsec pulse width.

--
Bill Sloman, Sydney
--
This email has been checked for viruses by Norton antivirus software.
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legg
2024-06-12 13:00:54 UTC
Permalink
Post by legg
<snip>
Post by legg
Post by Bill Sloman
Post by legg
Right, I see Q2 normally inverted.
C2 seems unneccessarily loaded.
If you are talking about the .asc file I posted on the 3rd June, Q2
isn't "normally inverted" - its mostly on, and it gets turned off for
the 30nsec in which the stretched pulse is being generated. Inverted
operation of a bipolar transistor is usually taken to mean running
current through them in the opposite direction than is seen in normal
operation.
Just returning to this, trying to see what determines the switch from
non-switching to astable operation (ECLTN0E - ECLTN0D). Misreading a
current and voltage waveform with similar color coding.
Post by Bill Sloman
C2 isn't carrying any current worth worrying about. It stabilises the
voltage at the base of Q3 against the base current drawn when the output
pulse is turned on and turned off, -6.7mA when it is turned on an +2mA
when it is turned off, and holds the voltage excursion down to 3.7mV,
not that I ever bothered working this out.
If you want to discuss when the circuit does and how it does it, feel
free, but this wasn't a good start.
Not so much interested in the circuit, as its reaction to model
parameters presented by similar devices.
You need to work out how the emitter-couple monostable works.
https://www.daenotes.com/electronics/digital-electronics/monostable-multivibrators-working-construction-types
actually does try to spell this out (in it's second section on
emitter-coupled monstables) . It doesn't do it well, but it does it well
enough that you should be able to work out what is going on, and keep
track of the base-emitter voltages across both transistors and their
effect on the collector current.
The Gummel-Poon transistor model keeeps track of the various currents
flowing in and out of each transistor junction while this is going on,
and subtle differences in the parameter values can give you different
currents (and different trajectories)
Post by legg
Not Beta, Tr or Tf in this case.
If you don't know what the circuit is doing, speculation about what the
model might be doing it is a bit pointless.
The emitter-coupled monstable isn't well understood here.
This is from the end of a long thread in 2013.
On Mar 9,
Post by legg
On Fri, 08 Mar 2013 01:18:53 -0600,
Post by Bill Sloman
On Thu, 07 Mar 2013 16:02:49 -0800, John Larkin
Post by legg
http://www.highlandtechnology.com/DSS/T240DS.shtml
---
That's not a pulse stretcher, cheater, that's a puls_generator_.
It's a one-shot. It has no internal trigger. It generates no pulses.
And neither you nor Jim have a clue as to how this might be done.
We have a customer who wants us to take this down to 10 ps
pulses. At that point, I'm not sure that I know how that might be done.
We're thinking about it.
http://books.google.co.nz/books?id=3D-pi4vP6xMOQC&pg=3DPA571&lpg=3DPA571&dq=
=3D%22emitter-coupled%22+monostable&source=3Dbl&ots=3DCFsGlVE2YN&sig=3DTUbj=
QhyQPk_cd5tj_UKlIhFVXt8&hl=3Den&sa=3DX&ei=3DTZw6UYmmPMeNyAHA4oHYAg&ved=3D0C=
EIQ6AEwAw#v=3Donepage&q=3D%22emitter-coupled%22%20monostable&f=3Dfalse
describes the emitter-coupled monostable. Put one together out of a
pair of wide-band transistors - BFR92 or better - with 33R up against
each base, and you can certainly get below 10nsec. Since the mechanism
depends on the change of base-emitter impedance with emitter current,
it isn't as easy as it might be to get a wide range of output pulse
widths.
Jim Thompson could probably remember a better solution for you. The
long-obsolete MC10198 ECL monostable
http://www.digchip.com/datasheets/parts/datasheet/343/MC10198-pdf.php
could just get down to 10nsec, but we used two of them when we wanted
to offer long pulses as well - being able to switch in bigger
capacitors put too much stray capacitance on the relevant input pin
for 10nsec operation.
Something boringly obvious with a constant current ramp and a fast
comparator would do the job, but - as with the MC10198, being able to
switch in bigger capacitors to generate much longer pulses is probably
incompatible with a 10nsec pulse width.
--
Bill Sloman, Sydney
The only parameters that I see in the ECLTN0E model that differs from
it's 'grouping', is a half order magnitude reduction in all junction
capacitances - this feature acting to prevent oscillatory behavior,
monostable or otherwise. It's ECL companion models oscillate (astable)
generally, despite Rbb parameters ranging over two orders of
magnitude, in this circuit configuration.

RL
Bill Sloman
2024-06-12 15:20:20 UTC
Permalink
Post by legg
Post by legg
<snip>
The only parameters that I see in the ECLTN0E model that differs from
it's 'grouping', is a half order magnitude reduction in all junction
capacitances - this feature acting to prevent oscillatory behavior,
monostable or otherwise. It's ECL companion models oscillate (astable)
generally, despite Rbb parameters ranging over two orders of
magnitude, in this circuit configuration.
The broad-band transistors - of which the BFR92 is the most obvious
example - famously have low collector base feedback capacitance, and a
very thin base layer (2V base to emitter breakdown voltage).

Looking at the parameters, without thinking about the transistor
behaviour that that they are intended to model, isn't a constructive or
useful activity.

When I was working for Cambridge Instruments were selling the EBMF10.5
electron beam microfabricator to write the fine-line masks that made
those sorts of devices.

Sometimes they were used to direct-write very fine features on
particularly exotic (and expensive) devices. On one occasion the
acceptance test for the machine was to write three wafers full of
devices, which - when diced and package - would have paid for the
million-odd dollar price of the machine.
--
Bill Sloman, Sydney
--
This email has been checked for viruses by Norton antivirus software.
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john larkin
2024-06-06 16:02:51 UTC
Permalink
Post by legg
<snip>
Post by Bill Sloman
Post by john larkin
Gosh, what a hideous mess, in many respects.
Do tell us why. You do claim to revel in electronic discussion.
Perhaps its the nonlinearity of the output stage, which is biased off.
I believe that a Spice model should be treated as an engineering
document: visible title, author, and correct latest-edit date, and it
should be neatly drawn, with coherent comments where appropriate. It
should be obvious where the inputs and outputs are, and important
nodes should have useful net names.

Versions should be identifiable as such.

A sim should be useful days or years after it's started. We often have
a README.txt file alongside the .asc files to explain the situation.

Most amateur Spice sims are messy tangled horrors.
Bill Sloman
2024-06-06 16:58:40 UTC
Permalink
Post by john larkin
Post by legg
<snip>
Post by Bill Sloman
Post by john larkin
Gosh, what a hideous mess, in many respects.
Do tell us why. You do claim to revel in electronic discussion.
Perhaps its the nonlinearity of the output stage, which is biased off.
I believe that a Spice model should be treated as an engineering
document: visible title, author, and correct latest-edit date, and it
should be neatly drawn, with coherent comments where appropriate. It
should be obvious where the inputs and outputs are, and important
nodes should have useful net names.
Versions should be identifiable as such.
If they are part of production documentation, all this goes without saying.

If we are posting a simple circuit here to make a point, it is less
obvious that we need to conform to your production standards.

What I posted was a very simple four transistor circuit - two fast NPNs
arranged as an emitter-coupled 30nsec monostable and a slower
long-tailed pair level shifter to turn the output into an ECL-level pulse.

Anybody who has done discrete transistor design should have been able to
parse it by looking at it.

The only messy object in the diagram was the Spice directive defining
the BFR92a Spice model, and the only reason I posted the .asc file was
to provide an example of that approach in action.

I've no idea why I put the sim together - it's paired with a bare
two-BFR92a emitter coupled monostable sim where the components were
strung between +5V and and -5V rails. The real life examples it was
probably drawn from had a +5V rail for the old TTL and a -4.5V rail for
the old ECL, though I did some work with the Gigabit Logic's GaAs parts
that needed two negative rails, -3.3V and -5.2V which was a real pain,
but that was just before ECLinPs and if you needed the speed, that was
what it took.
Post by john larkin
A sim should be useful days or years after it's started. We often have
a README.txt file alongside the .asc files to explain the situation.
You shouldn't have needed a README.txt file to tell you how to parse
that circuit.
Post by john larkin
Most amateur Spice sims are messy tangled horrors.
If you can't parse a circuit diagram, it always looks like a messy
tangled horror, and anything complicated always takes a certain amount
of inspection before it starts making sense.

If you though that what I posted was a "messy tangled horror" you are at
the "cat sat on the mat" level of schematic reading.
--
Bill Sloman, Sydney
--
This email has been checked for viruses by Norton antivirus software.
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piglet
2024-06-03 07:50:37 UTC
Permalink
Post by john larkin
On Sun, 2 Jun 2024 20:35:02 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
Post by john larkin
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
Yes it would be nice if a description of the part as well as the part
number could be included.
A sortable column of Ft would be nice for transistors. Lacking that,
sorting on Vce helps spot the RF parts. Low voltage suggests RF.
Ft isn’t one of the model parameters, guess you have to look for low Tf and
Tr transit times or low junction capacitances?
--
piglet
john larkin
2024-06-03 14:09:40 UTC
Permalink
On Mon, 3 Jun 2024 07:50:37 -0000 (UTC), piglet
Post by john larkin
On Sun, 2 Jun 2024 20:35:02 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
Post by john larkin
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
Yes it would be nice if a description of the part as well as the part
number could be included.
A sortable column of Ft would be nice for transistors. Lacking that,
sorting on Vce helps spot the RF parts. Low voltage suggests RF.
Ft isnÂ’t one of the model parameters, guess you have to look for low Tf and
Tr transit times or low junction capacitances?
Agreed, but reading hundreds of lines of fine print, or looking up
hundreds of data sheets, is a nuisance.

I sorted on lowest Vce and then found the capacitances and then looked
up the data sheets. LT Spice is not friendly to people with bad
vision.

I should have used one of the LS3xx parts. They have Vceo and Ic both
= 0.
Bill Sloman
2024-06-03 15:22:10 UTC
Permalink
Post by john larkin
On Mon, 3 Jun 2024 07:50:37 -0000 (UTC), piglet
Post by piglet
Post by john larkin
On Sun, 2 Jun 2024 20:35:02 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
Post by john larkin
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
Yes it would be nice if a description of the part as well as the part
number could be included.
A sortable column of Ft would be nice for transistors. Lacking that,
sorting on Vce helps spot the RF parts. Low voltage suggests RF.
Ft isn’t one of the model parameters, guess you have to look for low Tf and
Tr transit times or low junction capacitances >
Agreed, but reading hundreds of lines of fine print, or looking up
hundreds of data sheets, is a nuisance.
Looking at what distributors offer is easier and quicker.

They have an interest in offering their various customer the parts they
are likely to buy. Mouser did let me pick out the BFR92A pretty quickly.
Post by john larkin
I sorted on lowest Vce and then found the capacitances and then looked
up the data sheets. LT Spice is not friendly to people with bad
vision.
LTSpice is in the business of modelling the parts you select, not
selecting them for you
Post by john larkin
I should have used one of the LS3xx parts. They have Vceo and Ic both
= 0.
https://cms.nacsemi.com/content/AuthDatasheets/LISIS00171-1.pdf

All have an Ft of 200MHz. Not fast enough for ECL.
--
Bill Sloman, Sydney
Bill Sloman
2024-06-03 14:27:33 UTC
Permalink
Post by piglet
Post by john larkin
On Sun, 2 Jun 2024 20:35:02 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
Post by john larkin
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
Yes it would be nice if a description of the part as well as the part
number could be included.
A sortable column of Ft would be nice for transistors. Lacking that,
sorting on Vce helps spot the RF parts. Low voltage suggests RF.
Ft isn’t one of the model parameters, guess you have to look for low Tf and
Tr transit times or low junction capacitances?
Or you can look at wide-band transistors, pick one and plug the
manufacturers Spice model into LTSpice yourself, which is something I've
done from time to time (and posted the .asc files here), and John Larkin
doesn't seem to be able to manage.

He's just described the example I pulled out of the circuit file on my
computer as "hideous mess", which is inaccurate. Nobody would use +/-15V
rails to drive just that circuit, but if +/-15V rails are what you have
got, that circuit could solve a specific problem.
--
Bill sloman, Sydney
legg
2024-06-03 17:36:46 UTC
Permalink
Post by john larkin
On Sun, 2 Jun 2024 20:35:02 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
On Sun, 2 Jun 2024 19:46:14 -0400, "Edward Rawde"
Post by Edward Rawde
Post by john larkin
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
https://www.google.com/search?q=".model+BFR92A"
Post by john larkin
I want to make a model of the MC10EP89 gate.
That doesn't seem to be in the LT Spice library.
2SC3838K looks OK.
It's hard to pick parts, discrete or ICs, from the library.
Yes it would be nice if a description of the part as well as the part number could be included.
A sortable column of Ft would be nice for transistors. Lacking that,
sorting on Vce helps spot the RF parts. Low voltage suggests RF.
Tr and Tf are useful for models.

There are a few more ecl models in the current spreadsheet.
Some are duplicates from different revs or sources - variations
possibly due to published typos. (~ varying XTI, VJS, IKF, ITF)

http://ve3ute.ca/query/bjt_spice_parameter.zip

RL
Jeroen Belleman
2024-06-03 07:58:52 UTC
Permalink
Post by john larkin
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
I want to make a model of the MC10EP89 gate.
I always used the -now obsolete- BFR92A for such things.
That's a 5GHz Ft NPN that I used often. It's not in the
library, I think. Below the model. Mind the line wraps.

Jeroen Belleman

.model BFR92A NPN IS=4.11877E-016 BF=1.02639E+002 NF=9.97275E-001
VAF=6.26719E+001 IKF=3.20054E+000 ISE=4.01062E-015 NE=1.57708E+000
BR=1.81086E+001 NR=9.96202E-001 VAR=3.36915E+000 IKR=1.28155E+000
ISC=2.79905E-016 NC=1.07543E+000 RB=1.00000E+001 IRB=1.00000E-006
RBM=1.00000E+001 RE=1.16450E+000 RC=2.32000E+000 EG=1.11000E+000
XTI=3.00000E+000 CJE=8.90512E-013 VJE=6.00000E-001 MJE=2.58570E-001
TF=1.54973E-011 XTF=3.91402E+001 VTF=2.15279E+000 ITF=2.13776E-001
CJC=5.46563E-013 VJC=3.80824E-001 MJC=2.02935E-001
john larkin
2024-06-03 14:18:01 UTC
Permalink
On Mon, 3 Jun 2024 09:58:52 +0200, Jeroen Belleman
Post by Jeroen Belleman
Post by john larkin
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
I want to make a model of the MC10EP89 gate.
I always used the -now obsolete- BFR92A for such things.
That's a 5GHz Ft NPN that I used often. It's not in the
library, I think. Below the model. Mind the line wraps.
Jeroen Belleman
.model BFR92A NPN IS=4.11877E-016 BF=1.02639E+002 NF=9.97275E-001
VAF=6.26719E+001 IKF=3.20054E+000 ISE=4.01062E-015 NE=1.57708E+000
BR=1.81086E+001 NR=9.96202E-001 VAR=3.36915E+000 IKR=1.28155E+000
ISC=2.79905E-016 NC=1.07543E+000 RB=1.00000E+001 IRB=1.00000E-006
RBM=1.00000E+001 RE=1.16450E+000 RC=2.32000E+000 EG=1.11000E+000
XTI=3.00000E+000 CJE=8.90512E-013 VJE=6.00000E-001 MJE=2.58570E-001
TF=1.54973E-011 XTF=3.91402E+001 VTF=2.15279E+000 ITF=2.13776E-001
CJC=5.46563E-013 VJC=3.80824E-001 MJC=2.02935E-001
2SC3838K is in the library, and has Ft = 3.5G typically. It's good
enough for what I want to do now.

This is actually a bit faster than the MC10EP89:

Version 4
SHEET 1 1208 700
WIRE 112 -64 -16 -64
WIRE 272 -64 112 -64
WIRE 400 -64 272 -64
WIRE 576 -64 400 -64
WIRE 576 0 576 -64
WIRE -16 16 -16 -64
WIRE 272 16 272 -64
WIRE 400 96 400 -64
WIRE 272 144 272 96
WIRE 336 144 272 144
WIRE 576 144 576 80
WIRE -192 192 -368 192
WIRE -128 192 -192 192
WIRE -128 224 -128 192
WIRE 112 224 112 -64
WIRE -368 240 -368 192
WIRE 400 256 400 192
WIRE 576 256 400 256
WIRE 624 256 576 256
WIRE 640 256 624 256
WIRE -16 272 -16 96
WIRE 48 272 -16 272
WIRE -368 352 -368 320
WIRE -192 352 -368 352
WIRE -128 352 -128 304
WIRE -128 352 -192 352
WIRE 112 384 112 320
WIRE 400 384 112 384
WIRE 624 384 400 384
WIRE 640 384 624 384
WIRE -368 400 -368 352
WIRE -16 432 -16 272
WIRE 272 432 272 144
WIRE 400 432 400 384
WIRE 576 432 576 256
WIRE -16 560 -16 512
WIRE 272 560 272 512
WIRE 400 560 400 512
WIRE 576 560 576 512
FLAG 576 144 0
FLAG -192 192 A
FLAG -192 352 B
FLAG 624 256 X
FLAG 624 384 Y
FLAG -16 560 0
FLAG 272 560 0
FLAG -368 400 0
FLAG 400 560 0
FLAG 576 560 0
SYMBOL npn 336 96 R0
WINDOW 0 100 21 Left 2
WINDOW 3 71 55 Left 2
SYMATTR InstName Q1
SYMATTR Value 2SC3838K
SYMBOL voltage 576 -16 R0
WINDOW 0 48 40 Left 2
WINDOW 3 54 75 Left 2
SYMATTR InstName V1
SYMATTR Value 5
SYMBOL res 256 0 R0
WINDOW 0 -65 38 Left 2
WINDOW 3 -70 76 Left 2
SYMATTR InstName R2
SYMATTR Value 200
SYMBOL npn 48 224 R0
WINDOW 0 100 21 Left 2
WINDOW 3 71 55 Left 2
SYMATTR InstName Q2
SYMATTR Value 2SC3838K
SYMBOL res -32 0 R0
WINDOW 0 53 46 Left 2
WINDOW 3 48 80 Left 2
SYMATTR InstName R1
SYMATTR Value 200
SYMBOL bi -16 432 R0
WINDOW 0 58 111 Left 2
WINDOW 3 -343 170 Left 2
SYMATTR InstName B1
SYMATTR Value I=4m*( 1 - tanh (200 * ( V(B)-V(A) ) ) )
SYMBOL res -144 208 R0
WINDOW 0 -60 48 Left 2
WINDOW 3 -69 79 Left 2
SYMATTR InstName R5
SYMATTR Value 10K
SYMBOL bi 272 432 R0
WINDOW 0 -91 109 Left 2
WINDOW 3 -100 169 Left 2
SYMATTR InstName B2
SYMATTR Value I=4m*( 1 - tanh (200 * ( V(A)-V(B) ) ) )
SYMBOL voltage -368 224 R0
WINDOW 0 -58 -21 Left 2
WINDOW 3 -94 -80 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value PULSE(-1 1 1n 500p 500p 2n)
SYMBOL res 384 416 R0
WINDOW 0 53 40 Left 2
WINDOW 3 47 71 Left 2
SYMATTR InstName R3
SYMATTR Value 200
SYMBOL res 560 416 R0
WINDOW 0 49 36 Left 2
WINDOW 3 46 71 Left 2
SYMATTR InstName R4
SYMATTR Value 200
TEXT -288 48 Left 2 !.tran 5n
TEXT 416 232 Left 2 ;1.6v pp
TEXT -296 -40 Left 2 ;MC10EP89
TEXT 136 360 Left 2 ;1.6v pp
TEXT -328 0 Left 2 ;JL Jun 2 2024
Bill Sloman
2024-06-03 15:46:01 UTC
Permalink
Post by john larkin
On Mon, 3 Jun 2024 09:58:52 +0200, Jeroen Belleman
Post by Jeroen Belleman
Post by john larkin
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
I want to make a model of the MC10EP89 gate.
I always used the -now obsolete- BFR92A for such things.
That's a 5GHz Ft NPN that I used often. It's not in the
library, I think. Below the model. Mind the line wraps.
Jeroen Belleman
.model BFR92A NPN IS=4.11877E-016 BF=1.02639E+002 NF=9.97275E-001
VAF=6.26719E+001 IKF=3.20054E+000 ISE=4.01062E-015 NE=1.57708E+000
BR=1.81086E+001 NR=9.96202E-001 VAR=3.36915E+000 IKR=1.28155E+000
ISC=2.79905E-016 NC=1.07543E+000 RB=1.00000E+001 IRB=1.00000E-006
RBM=1.00000E+001 RE=1.16450E+000 RC=2.32000E+000 EG=1.11000E+000
XTI=3.00000E+000 CJE=8.90512E-013 VJE=6.00000E-001 MJE=2.58570E-001
TF=1.54973E-011 XTF=3.91402E+001 VTF=2.15279E+000 ITF=2.13776E-001
CJC=5.46563E-013 VJC=3.80824E-001 MJC=2.02935E-001
2SC3838K is in the library, and has Ft = 3.5G typically. It's good
enough for what I want to do now.
<snipped two transistor model>

It is worth noting that even 3.5GHz transistors tend to need
base-stopper resistors in real life. Collector-base capacitive feedback
can make them self-oscillate without it. Phil Hobbs has found two Murata
ferrite bead/chips which are specified as presenting resistive
impedances of 60R and 200R at 5GHz which seems to do the job too.

Jim Thompson designed that kind of integrated circuit, but he's been
dead for a while now.
--
Bill Sloman, Sydney
legg
2024-06-03 12:33:14 UTC
Permalink
Post by john larkin
There are many NPNs in the standard LT Spice library.
Does anyone know of a fast, RF type, transistor? It's hard to tell
from the jillion lines of fine-print parameters.
I want to make a model of the MC10EP89 gate.
From the standard.bjt spice parameter spreadsheet, compiled some time
ago, there are a few ecl spice models.

.MODEL ECLTN04P75 NPN(IS=6.50E-18 ISE=3.40E-16 ISC=0 ISS=0.0 XTI=4
BF=120 BR=10 IKF=8.0E-3 IKR=7E-4 XTB=0.73 VAF=30 VAR=5
VJE=0.9 VJC=0.67 VJS=0.75 RE=17.5 RB=378.5 RC=74 RBM=120
CJE=2.36E=14 CJS=5.38E-14 CJC=2.74E-14 XCJC=.3 FC=0.9 NF=1 NR=1 NE=2
NC=2 NS=1.0 MJE=0.4 MJC=0.32 MJS=0.4 TF=8E-12 TR=1E-9 Trb1=0 Tre1=0.0
Trc1=0.0 TRM1=0.0 IRB=1E-5 ITF=2.1E-2 VTF=1.4 XTF=10 GAMMA=1E-11
Rco=0 Nk=0.5 PTF=0 EG=1.1 KF=0 AF=1 Qco=0 Vo=10 Quasimod=0
IBVbe=1E-10
Bvbe=1E5 BVcbo=1E5 Vceo=5.5 Icrating=0 MFG=1.74u_x_4.75u_emitter)

.MODEL ECLTN06 NPN(IS=8.56E-18 ISE=4.48E-16 ISC=0 ISS=0.0 XTI=4
BF=120 BR=10 IKF=1.05E-2 IKR=9.22E-4 XTB=0.73 VAF=30 VAR=5
VJE=0.9 VJC=0.67 VJS=0.75 RE=13.3 RB=291.4 RC=62.7 RBM=95
CJE=2.99E-14 CJS=6.09E-14 CJC=3.12E-14 XCJC=.3 FC=0.9 NF=1 NR=1 NE=2
NC=2 NS=1.0 MJE=0.4 MJC=0.32 MJS=0.4 TF=8E-12 TR=1E-9 Trb1=0 Tre1=0.0
Trc1=0.0 TRM1=0.0 IRB=1.32E-5 ITF=2.76E-2 VTF=1.4 XTF=10 GAMMA=1E-11
Rco=0 Nk=0.5 PTF=0 EG=1.1 KF=0 AF=1 Qco=0 Vo=10 Quasimod=0 IBVbe=1E-10
Bvbe=1E5 BVcbo=1E5 Vceo=5.5 Icrating=0 MFG=1.75u_x_6.0u_emitter)

.MODEL ECLTN13P5 NPN(IS=2.09E-17 ISE=1.09E-15 ISC=0 ISS=0.0 XTI=4
BF=120 BR=10 IKF=2.57E-2 IKR=2.25E-3 XTB=0.73 VAF=30 VAR=5
VJE=0.9 VJC=0.67 VJS=0.75 RE=5.44 RB=122.6 RC=32.8 RBM=42.2
CJE=6.74E-14 CJS=1.03E-13 CJC=5.38E-14 XCJC=.3 FC=0.9 NF=1 NR=1 NE=2
NC=2 NS=1.0 MJE=0.4 MJC=0.32 MJS=0.4 TF=8E-12 TR=1E-9 Trb1=0 Tre1=0.0
Trc1=0.0 TRM1=0.0 IRB=3.22E-5 ITF=6.75E-2 VTF=1.4 XTF=10 GAMMA=1E-11
Rco=0 Nk=0.5 PTF=0 EG=1.1 KF=0 AF=1 Qco=0 Vo=10 Quasimod=0 IBVbe=1E-10
Bvbe=1E5 BVcbo=1E5 Vceo=5.5 Icrating=0 MFG=1.75u_x_13.5u_emitter)

.MODEL ECLTN4 NPN(IS=5.27E-18 ISE=2.75E-16 ISC=0 ISS=0.0 XTI=4
BF=120 BR=10 IKF=6.48E-3 IKR=5.67E-4 XTB=0.73 VAF=30 VAR=5
VJE=0.9 VJC=0.67 VJS=0.75 RE=21.6 RB=461.6 RC=83.1 RBM=142.5
CJE=19.9E-15 CJS=49.6E-15 CJC=25.1E-15 XCJC=0.3 FC=0.9 NF=1 NR=1 NE=2
NC=2 NS=1.0 MJE=0.4 MJC=0.32 MJS=0.4 TF=8E-12 TR=1E-9 Trb1=0 Tre1=0.0
Trc1=0.0 TRM1=0.0 IRB=8.1E-6 ITF=1.7E-2 VTF=1.4 XTF=10 GAMMA=1E-11
Rco=0 Nk=0.5 PTF=0 EG=1.1 KF=0 AF=1 Qco=0 Vo=10 Quasimod=0 IBVbe=1E-10
Bvbe=1E5 BVcbo=1E5 Vceo=5.5 Icrating=0 MFG=1.75u_x_4.0u_emitter)

.MODEL ECLTNECLIPS NPN(IS=2.27E-16 ISE=1.19E-14 ISC=0 ISS=0.0 XTI=4
BF=120 BR=10 IKF=0.279 IKR=2.44E-2 XTB=0.73 VAF=30 VAR=5
VJE=0.9 VJC=0.67 VJS=0.75 RE=0.501 RB=15.98 RC=11.1 RBM=4.17
CJE=6.11E-13 CJS=6.68E-13 CJC=4.4E-13 XCJC=.3 FC=0.9 NF=1 NR=1 NE=2
NC=2 NS=1.0 MJE=0.4 MJC=0.32 MJS=0.4 TF=8E-12 TR=1E-9 Trb1=0 Tre1=0.0
Trc1=0.0 TRM1=0.0 IRB=3.49E-4 ITF=0.733 VTF=1.4 XTF=10 GAMMA=1E-11
Rco=0 Nk=0.5 PTF=0 EG=1.1 KF=0 AF=1 Qco=0 Vo=10 Quasimod=0 IBVbe=1E-10
Bvbe=1E5 BVcbo=1E5 Vceo=5.5 Icrating=0 MFG=ECLout)


This is a simple text copy/paste into notepad, with tabs removed and
carriage returns added.

RL
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