Driver to drive?

John Larkin · Feb 9, 2012

On 9 Feb 2012 09:24:41 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2012-02-08, John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
On Wed, 08 Feb 2012 05:44:39 -0500, JW <none@dev.null> wrote:

On Tue, 07 Feb 2012 17:59:33 -0800 The_Giant_Rat_of_Sumatra

[...] the usual whinging.

That's British for "whining", isn't it? How is that pronounced?

pronunced win-jing

I'd consider whining to be high pitched and whinging moderate to
low pitched so it's closer to grumbling or moaning than to whining.

Well, then I think Ratso is whining.

--

John Larkin, President Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

amdx · Feb 9, 2012

On 2/9/2012 8:44 AM, The_Giant_Rat_of_Sumatra wrote:

On Thu, 09 Feb 2012 13:12:15 +0000, Pomegranate Bastard
pommyB@dsl.pipex.com> wrote:

Would you please supply some evidence of your claims?

You don't even know what a 10Gb/s optical port looks like either,
jackass.

You are truly pathetic, and a total loser.

The only response a retard like you knows is "stalk and jab".

Hey Rat,
Please quietly leave my thread!
Thanks, Mikek

Pomegranate Bastard · Feb 9, 2012

On Thu, 09 Feb 2012 06:44:45 -0800, The_Giant_Rat_of_Sumatra
<GeorgeTirebiter@drmemory.org> wrote:

On Thu, 09 Feb 2012 13:12:15 +0000, Pomegranate Bastard
pommyB@dsl.pipex.com> wrote:

Would you please supply some evidence of your claims?

You don't even know what a 10Gb/s optical port looks like either,
jackass.

You are truly pathetic, and a total loser.

The only response a retard like you knows is "stalk and jab".

Would you please supply some evidence of your claims?

Lostgallifreyan · Feb 9, 2012

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:4pm7j79ijbdob79c6pk8herd3q242dd2ht@4ax.com:

Elaborate on the follower conditions... are you saying output is below
rail? What load did you have, if any? I'm thinking on a
generalized OpAmp model which definitely solves such issues, but am
embroiled in other mathematical niceties at the moment ;-)

What is the unity gain stabilizing capacitance issue?

No hurry, I just nudged because I know that with time, it gets harder to
return to any specific problem. (I'm learning C and some API stuff so I have
the same problem here).

Anyway, it's no-load, -1.14V, 1K pad, -1.022V, 100R, -0.198.6V, so definitely
iffy, as no amp can provide a DC voltage below its negative with any actual
drive current. Inductive or capacitive spikes on pulses, sure, but not with
steady DC.

The stabilising needed is to prevent a small fast noisy oscillation. Same
reason it would usually be applied. The CA3140 is internally stabilised, so
needs something done to prevent us having to add it externally. We can do it,
but if we have to, it's safe to assume the model isn't accurate enough.

----

Remember I asked some other questions? Basically, what zener voltages for
those four zeners in that schematic. I haven't ruled out playing around with
that, and some minimum Spice parameters like Xti and suchlike to use to
modify default LTspice native models for diodes and BJT and MOSFET for this
NIMOS amp. I've seen many op-amp models that do this, using as little as
three or four specied parameters, which suggests that even an ignoramus like
me has a fighting chance of coming up with the goods purely by trial and
error if you can tell me which parameters are the most important ones to
modify for each internal part. I imagine there may be something specific to
the BIMOS contruction that can guide to a choice for those parameters.

In short, my insticts tell me that staying as close to the original
schematic, and using values common to each sub-modelled part, will get a
useable model. It's a different approach to yours, but I want to try it.

Feb 9, 2012

On Feb 9, 12:45 am, josephkk <joseph_barr...@sbcglobal.net> wrote:

On Sun, 05 Feb 2012 14:06:30 -0700, Jim Thompson wrote:
On Sun, 05 Feb 2012 15:31:32 -0500, Phil Hobbs wrote:
Jim Thompson wrote:

It must be hell to be manic depressive.

Nah, some of my favourite transistors are bipolar.

Mine, too >:-}

Often useful for tran' sisters. Not necessarily good for engineers.

One wonders about that. Looking through history, the more brilliant
someone is, the more likely they're crazy.

--
Cheers,
James Arthur

Lostgallifreyan · Feb 9, 2012

Lostgallifreyan <no-one@nowhere.net> wrote in
news:Xns9FF4A3F402FE2zoodlewurdle@216.196.109.145:

1K pad

???
I'm fairly sure I typed 'load' but never mind..

Jim Thompson · Feb 9, 2012

On Thu, 09 Feb 2012 10:07:02 -0600, Lostgallifreyan
<no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:4pm7j79ijbdob79c6pk8herd3q242dd2ht@4ax.com:

Elaborate on the follower conditions... are you saying output is below
rail? What load did you have, if any? I'm thinking on a
generalized OpAmp model which definitely solves such issues, but am
embroiled in other mathematical niceties at the moment ;-)

What is the unity gain stabilizing capacitance issue?

No hurry, I just nudged because I know that with time, it gets harder to
return to any specific problem. (I'm learning C and some API stuff so I have
the same problem here).

Anyway, it's no-load, -1.14V, 1K pad, -1.022V, 100R, -0.198.6V, so definitely
iffy, as no amp can provide a DC voltage below its negative with any actual
drive current. Inductive or capacitive spikes on pulses, sure, but not with
steady DC.

The stabilising needed is to prevent a small fast noisy oscillation. Same
reason it would usually be applied. The CA3140 is internally stabilised, so
needs something done to prevent us having to add it externally. We can do it,
but if we have to, it's safe to assume the model isn't accurate enough.

----

Remember I asked some other questions? Basically, what zener voltages for
those four zeners in that schematic. I haven't ruled out playing around with
that, and some minimum Spice parameters like Xti and suchlike to use to
modify default LTspice native models for diodes and BJT and MOSFET for this
NIMOS amp. I've seen many op-amp models that do this, using as little as
three or four specied parameters, which suggests that even an ignoramus like
me has a fighting chance of coming up with the goods purely by trial and
error if you can tell me which parameters are the most important ones to
modify for each internal part. I imagine there may be something specific to
the BIMOS contruction that can guide to a choice for those parameters.

In short, my insticts tell me that staying as close to the original
schematic, and using values common to each sub-modelled part, will get a
useable model. It's a different approach to yours, but I want to try it.

The CA3140 data sheet and _schematic_ are suspect. There are
conflicting specifications. As an I/C designer the schematic has an
"odor of mendacity" about it

The model I'm pondering in my head takes my present basic model with
GDC, GBW, slew-rate, Rout, phase-margin, and positive and negative
swing limit specifiable... but modified as follows:

Rout => Rout-sourcing, Rout-sinking (separate values)
Current limit sourcing and sinking (separate values)
Power supply pins will reflect load _and_ quiescent currents
Output swing limits specifiable relative to rail potentials

It may even show recovery time from slamming into rails... not quite
sure yet, but I think so

John Larkin · Feb 9, 2012

On Thu, 9 Feb 2012 07:08:07 -0800 (PST), dagmargoodboat@yahoo.com
wrote:

On Feb 9, 12:45 am, josephkk <joseph_barr...@sbcglobal.net> wrote:
On Sun, 05 Feb 2012 14:06:30 -0700, Jim Thompson wrote:
On Sun, 05 Feb 2012 15:31:32 -0500, Phil Hobbs wrote:
Jim Thompson wrote:

It must be hell to be manic depressive.

Nah, some of my favourite transistors are bipolar.

Mine, too >:-}

Often useful for tran' sisters. Not necessarily good for engineers.

One wonders about that. Looking through history, the more brilliant
someone is, the more likely they're crazy.

Of course. Ideas come from permeability in the barriers that segrate
ideas and brain functions. Schitzophrenia comes from a more complete
breakdown.

I guess attachment to reality works the same way. If you can
reasonably suspend conventional concepts of what's possible and
impossible, you can better explore the solution space. If you suspend
all limits on the possible, you become a loonie.

Here's another interesting relationship: the more politically powerful
a person is, the more likely that they are sociopaths.

--

John Larkin, President Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

Lostgallifreyan · Feb 9, 2012

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:tvr7j7lk7esh7cuaekgtd23lsnpm0tnvcq@4ax.com:

The CA3140 data sheet and _schematic_ are suspect. There are
conflicting specifications. As an I/C designer the schematic has an
"odor of mendacity" about it

But you see my problem... On the one hand I am told I have a datasheet that
lies, on the other, a model that puts out negative DC in a way that might
have precluded any need for switchmode generators of nagtive rails had it
really worked that way in silicon.

Either way I'm at a loss.

John Fields · Feb 9, 2012

On Wed, 08 Feb 2012 11:49:37 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Wed, 08 Feb 2012 08:49:11 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Wed, 8 Feb 2012 07:32:11 -0800 (PST), George Herold
gherold@teachspin.com> wrote:

On Feb 8, 9:48 am, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My-
Web-Site.com> wrote:
On Tue, 07 Feb 2012 22:09:33 -0800, John Larkin

jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
On Tue, 7 Feb 2012 19:39:47 -0800 (PST), George Herold
gher...@teachspin.com> wrote:

On Feb 7, 9:53 pm, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My-
Web-Site.com> wrote:
On Tue, 07 Feb 2012 18:40:31 -0800, John Larkin

jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
On Sun, 5 Feb 2012 17:22:24 -0800 (PST), dagmargoodb...@yahoo.com
wrote:

On Feb 5, 5:39 pm, Jim Thompson wrote:
On Sun, 05 Feb 2012 14:08:18 -0800, John Larkin wrote:
On Sun, 05 Feb 2012 13:28:58 -0700, Jim Thompson wrote:

So far, life has been a huge amount of fun. But what does that have to
do with diodes?

The same as talking amps of current in a 1N4148.

http://www.nxp.com/documents/data_sheet/1N4148_1N4448.pdf

Looks effectively ohmic above 50mA (Fig. 3).

Yup. The slope is just about 1 ohm. The dynamic impedance of a PN
junction is 1 ohm at 25 mA.

Closer to 26mA ;-)

...Jim Thompson
--
[snip]

- Show quoted text -

1 ohm is a pretty good number for a small junction. I measured a
2n3904 about the same.

Neat, how the resistance goes to ~1.5 ohms at ~450K.

George H.

Yup, the ohmic part has a positive TC.

Huh? It does, but George was taking about the kT/qI portion...
450/300=1.5 ;-)

Opps, I was talking about the resistive part. It should also scale
with the absolute temperature, if the resistance is from some hunk of
'metal'.

Yes, I thought you were. JT's comment didn't make sense.

Why? Because you don't understand kT/qI ?

Perfect diode, no resistive term, DYNAMIC impedance scales linearly
with temperature (°K). So a perfect diode operating a 26mA at 300°K
has a DYNAMIC impedance of 1 Ohm; and 1.5 Ohm DYNAMIC impedance at
450°K.

Perhaps someone would plot 1N4148 forward drop on LOG paper so we can
easily see the bulk R breakpoint (and the _dirt_ at low currents, the
ISR coefficient in the model).

...Jim Thompson

---
Not 1N4148 per se, but silicon in general.

news:r1u7j79mdi2c4g5bdtpcap7f1oopccrkup@4ax.com

From Motorola's 1980 silicon rectifier data manual.

--
JF

Jim Thompson · Feb 9, 2012

On Thu, 09 Feb 2012 10:36:23 -0600, Lostgallifreyan
<no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:tvr7j7lk7esh7cuaekgtd23lsnpm0tnvcq@4ax.com:

The CA3140 data sheet and _schematic_ are suspect. There are
conflicting specifications. As an I/C designer the schematic has an
"odor of mendacity" about it

But you see my problem... On the one hand I am told I have a datasheet that
lies, on the other, a model that puts out negative DC in a way that might
have precluded any need for switchmode generators of nagtive rails had it
really worked that way in silicon.

Either way I'm at a loss.

Jim Thompson · Feb 9, 2012

On Thu, 09 Feb 2012 10:55:03 -0600, John Fields
<jfields@austininstruments.com> wrote:

On Wed, 08 Feb 2012 11:49:37 -0700, Jim Thompson
To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Wed, 08 Feb 2012 08:49:11 -0800, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Wed, 8 Feb 2012 07:32:11 -0800 (PST), George Herold
gherold@teachspin.com> wrote:

On Feb 8, 9:48 am, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My-
Web-Site.com> wrote:
On Tue, 07 Feb 2012 22:09:33 -0800, John Larkin

jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
On Tue, 7 Feb 2012 19:39:47 -0800 (PST), George Herold
gher...@teachspin.com> wrote:

On Feb 7, 9:53 pm, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My-
Web-Site.com> wrote:
On Tue, 07 Feb 2012 18:40:31 -0800, John Larkin

jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
On Sun, 5 Feb 2012 17:22:24 -0800 (PST), dagmargoodb...@yahoo.com
wrote:

On Feb 5, 5:39 pm, Jim Thompson wrote:
On Sun, 05 Feb 2012 14:08:18 -0800, John Larkin wrote:
On Sun, 05 Feb 2012 13:28:58 -0700, Jim Thompson wrote:

So far, life has been a huge amount of fun. But what does that have to
do with diodes?

The same as talking amps of current in a 1N4148.

http://www.nxp.com/documents/data_sheet/1N4148_1N4448.pdf

Looks effectively ohmic above 50mA (Fig. 3).

Yup. The slope is just about 1 ohm. The dynamic impedance of a PN
junction is 1 ohm at 25 mA.

Closer to 26mA ;-)

...Jim Thompson
--
[snip]

- Show quoted text -

1 ohm is a pretty good number for a small junction. I measured a
2n3904 about the same.

Neat, how the resistance goes to ~1.5 ohms at ~450K.

George H.

Yup, the ohmic part has a positive TC.

Huh? It does, but George was taking about the kT/qI portion...
450/300=1.5 ;-)

Opps, I was talking about the resistive part. It should also scale
with the absolute temperature, if the resistance is from some hunk of
'metal'.

Yes, I thought you were. JT's comment didn't make sense.

Why? Because you don't understand kT/qI ?

Perfect diode, no resistive term, DYNAMIC impedance scales linearly
with temperature (°K). So a perfect diode operating a 26mA at 300°K
has a DYNAMIC impedance of 1 Ohm; and 1.5 Ohm DYNAMIC impedance at
450°K.

Perhaps someone would plot 1N4148 forward drop on LOG paper so we can
easily see the bulk R breakpoint (and the _dirt_ at low currents, the
ISR coefficient in the model).

...Jim Thompson

---
Not 1N4148 per se, but silicon in general.

news:r1u7j79mdi2c4g5bdtpcap7f1oopccrkup@4ax.com

From Motorola's 1980 silicon rectifier data manual.

Yep. Actually, that double curve reminds me that, if you do that for
IB _and_ IC of a _transistor_, you can derive all kinds of model
parameters. I did that, with assistance from my son Aaron, in the
early '80's writing the solution of that problem as a Pascal
executable. (Damn! I thought nothing of it then, but Aaron was only
12 years old at the time! He's gone on to be in charge of all
software creation and utilization for the world's largest call-center
corporation... working from his farm house in San Tan Valley, AZ

Lostgallifreyan · Feb 9, 2012

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:npv7j7d32rmu10oq7u2ifup1ner08e4i0b@4ax.com:

I modeled the output with only a current limit... no swing bounds
except for the feedback. YOU violated the rules ;-)

How so?

All I did was try to measure the thing according your
directions... It's looked extremely inconsistent so I understand that it can
be hard to model, but I don't think working from a basic model will work,
other than to create an idea of what it should do, especially if it ends up
outputing steady voltages below its nagative rail. What's needed is a model
of what it does.

Jim Thompson · Feb 9, 2012

On Thu, 09 Feb 2012 11:33:17 -0600, Lostgallifreyan
<no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:npv7j7d32rmu10oq7u2ifup1ner08e4i0b@4ax.com:

I modeled the output with only a current limit... no swing bounds
except for the feedback. YOU violated the rules ;-)

How so? All I did was try to measure the thing according your
directions... It's looked extremely inconsistent so I understand that it can
be hard to model, but I don't think working from a basic model will work,
other than to create an idea of what it should do, especially if it ends up
outputing steady voltages below its nagative rail. What's needed is a model
of what it does.

Lostgallifreyan · Feb 9, 2012

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:h528j7pq8pc7kh34dllugouncb7ageim8p@4ax.com:

On Thu, 09 Feb 2012 11:33:17 -0600, Lostgallifreyan
no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote
in news:npv7j7d32rmu10oq7u2ifup1ner08e4i0b@4ax.com:

I modeled the output with only a current limit... no swing bounds
except for the feedback. YOU violated the rules ;-)

How so? All I did was try to measure the thing according your
directions... It's looked extremely inconsistent so I understand that it
can be hard to model, but I don't think working from a basic model will
work, other than to create an idea of what it should do, especially if
it ends up outputing steady voltages below its nagative rail. What's
needed is a model of what it does.

Didn't you say you input a voltage below negative rail?

...Jim Thompson

It doesn't matter. I used a -2V modelled input, but it's a high resistance
input (several terohms probably) and I put a 1Meg resistor on it anyway just
to be sure. No real world amp will maintain a DC output voltage below its
negative supply rail, into a 1K load and still hold over a volt below that
rail. That takes a lot more energy than will ever leak though that input from
a -2V source. You can't get something for nothing in a real op-amp.

Jim Thompson · Feb 9, 2012

On Thu, 09 Feb 2012 12:50:57 -0600, Lostgallifreyan
<no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:h528j7pq8pc7kh34dllugouncb7ageim8p@4ax.com:

On Thu, 09 Feb 2012 11:33:17 -0600, Lostgallifreyan
no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote
in news:npv7j7d32rmu10oq7u2ifup1ner08e4i0b@4ax.com:

I modeled the output with only a current limit... no swing bounds
except for the feedback. YOU violated the rules ;-)

How so? All I did was try to measure the thing according your
directions... It's looked extremely inconsistent so I understand that it
can be hard to model, but I don't think working from a basic model will
work, other than to create an idea of what it should do, especially if
it ends up outputing steady voltages below its nagative rail. What's
needed is a model of what it does.

Didn't you say you input a voltage below negative rail?

...Jim Thompson

It doesn't matter. I used a -2V modelled input, but it's a high resistance
input (several terohms probably) and I put a 1Meg resistor on it anyway just
to be sure. No real world amp will maintain a DC output voltage below its
negative supply rail, into a 1K load and still hold over a volt below that
rail. That takes a lot more energy than will ever leak though that input from
a -2V source. You can't get something for nothing in a real op-amp.

Lostgallifreyan · Feb 9, 2012

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:vn68j7hd5i7ldcjramfhln4himlud6pk9h@4ax.com:

On Thu, 09 Feb 2012 12:50:57 -0600, Lostgallifreyan
no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote
in news:h528j7pq8pc7kh34dllugouncb7ageim8p@4ax.com:

On Thu, 09 Feb 2012 11:33:17 -0600, Lostgallifreyan
no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote
in news:npv7j7d32rmu10oq7u2ifup1ner08e4i0b@4ax.com:

I modeled the output with only a current limit... no swing bounds
except for the feedback. YOU violated the rules ;-)

How so? All I did was try to measure the thing according your
directions... It's looked extremely inconsistent so I understand that
it can be hard to model, but I don't think working from a basic model
will work, other than to create an idea of what it should do,
especially if it ends up outputing steady voltages below its nagative
rail. What's needed is a model of what it does.

Didn't you say you input a voltage below negative rail?

...Jim Thompson

It doesn't matter. I used a -2V modelled input, but it's a high
resistance input (several terohms probably) and I put a 1Meg resistor on
it anyway just to be sure. No real world amp will maintain a DC output
voltage below its negative supply rail, into a 1K load and still hold
over a volt below that rail. That takes a lot more energy than will ever
leak though that input from a -2V source. You can't get something for
nothing in a real op-amp.

You be not paying attention. Read every iota of what I've written
today.

it really does not matter WHAT happens here. You're asking me to accept a
model that will output such that it holds -1V below its negative rail. I will
not do that. No-one should. Real amps don't do this.

You can take any 1Meg resitor, Spice or otherwise, it won't hold more than
200 mV across a 1K resistor. Your model is generating, it is not merely being
powered by a virtual supply, it IS one!

Browbeating me into appearing like a lazy noob is not going to distract
anyone from this issue, as the model you posted is out there now for anyone
to prove this.

Jim Thompson · Feb 9, 2012

On Thu, 09 Feb 2012 13:50:52 -0600, Lostgallifreyan
<no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:vn68j7hd5i7ldcjramfhln4himlud6pk9h@4ax.com:

On Thu, 09 Feb 2012 12:50:57 -0600, Lostgallifreyan
no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote
in news:h528j7pq8pc7kh34dllugouncb7ageim8p@4ax.com:

On Thu, 09 Feb 2012 11:33:17 -0600, Lostgallifreyan
no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote
in news:npv7j7d32rmu10oq7u2ifup1ner08e4i0b@4ax.com:

I modeled the output with only a current limit... no swing bounds
except for the feedback. YOU violated the rules ;-)

How so? All I did was try to measure the thing according your
directions... It's looked extremely inconsistent so I understand that
it can be hard to model, but I don't think working from a basic model
will work, other than to create an idea of what it should do,
especially if it ends up outputing steady voltages below its nagative
rail. What's needed is a model of what it does.

Didn't you say you input a voltage below negative rail?

...Jim Thompson

It doesn't matter. I used a -2V modelled input, but it's a high
resistance input (several terohms probably) and I put a 1Meg resistor on
it anyway just to be sure. No real world amp will maintain a DC output
voltage below its negative supply rail, into a 1K load and still hold
over a volt below that rail. That takes a lot more energy than will ever
leak though that input from a -2V source. You can't get something for
nothing in a real op-amp.

You be not paying attention. Read every iota of what I've written
today.

it really does not matter WHAT happens here. You're asking me to accept a
model that will output such that it holds -1V below its negative rail. I will
not do that. No-one should. Real amps don't do this.

You can take any 1Meg resitor, Spice or otherwise, it won't hold more than
200 mV across a 1K resistor. Your model is generating, it is not merely being
powered by a virtual supply, it IS one!

Browbeating me into appearing like a lazy noob is not going to distract
anyone from this issue, as the model you posted is out there now for anyone
to prove this.

Gawd! You're so dense you've become a Slowman look-alike.

In... Message-ID: <npv7j7d32rmu10oq7u2ifup1ner08e4i0b@4ax.com>

I said, "I modeled the output with only a current limit... no swing
bounds except for the feedback." [YOUR feedback loop]

In... Message-ID: <tvr7j7lk7esh7cuaekgtd23lsnpm0tnvcq@4ax.com>

I said, "The model I'm pondering in my head takes my present basic
model..."

[My "present basic model" is not what I tried to use to fit the CAcrap
(because of its weirdness), look on my website or Google to see it.]

"with GDC, GBW, slew-rate, Rout, phase-margin, and positive and
negative swing limit specifiable... but modified as follows:

Rout => Rout-sourcing, Rout-sinking (separate values)
Current limit sourcing and sinking (separate values)
Power supply pins will reflect load _and_ quiescent currents
Output swing limits specifiable relative to rail potentials

It may even show recovery time from slamming into rails... not quite
sure yet, but I think so

Lostgallifreyan · Feb 9, 2012

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote in
news:st88j7p1nhamcf5abpisndq0udtbjv8jdj@4ax.com:

On Thu, 09 Feb 2012 13:50:52 -0600, Lostgallifreyan
no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote
in news:vn68j7hd5i7ldcjramfhln4himlud6pk9h@4ax.com:

On Thu, 09 Feb 2012 12:50:57 -0600, Lostgallifreyan
no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote
in news:h528j7pq8pc7kh34dllugouncb7ageim8p@4ax.com:

On Thu, 09 Feb 2012 11:33:17 -0600, Lostgallifreyan
no-one@nowhere.net> wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com
wrote in news:npv7j7d32rmu10oq7u2ifup1ner08e4i0b@4ax.com:

I modeled the output with only a current limit... no swing bounds
except for the feedback. YOU violated the rules ;-)

How so? All I did was try to measure the thing according your
directions... It's looked extremely inconsistent so I understand
that it can be hard to model, but I don't think working from a basic
model will work, other than to create an idea of what it should do,
especially if it ends up outputing steady voltages below its
nagative rail. What's needed is a model of what it does.

Didn't you say you input a voltage below negative rail?

...Jim Thompson

It doesn't matter. I used a -2V modelled input, but it's a high
resistance input (several terohms probably) and I put a 1Meg resistor
on it anyway just to be sure. No real world amp will maintain a DC
output voltage below its negative supply rail, into a 1K load and
still hold over a volt below that rail. That takes a lot more energy
than will ever leak though that input from a -2V source. You can't get
something for nothing in a real op-amp.

You be not paying attention. Read every iota of what I've written
today.

it really does not matter WHAT happens here. You're asking me to accept
a model that will output such that it holds -1V below its negative rail.
I will not do that. No-one should. Real amps don't do this.

You can take any 1Meg resitor, Spice or otherwise, it won't hold more
than 200 mV across a 1K resistor. Your model is generating, it is not
merely being powered by a virtual supply, it IS one!

Browbeating me into appearing like a lazy noob is not going to distract
anyone from this issue, as the model you posted is out there now for
anyone to prove this.

Gawd! You're so dense you've become a Slowman look-alike.

In... Message-ID: <npv7j7d32rmu10oq7u2ifup1ner08e4i0b@4ax.com

I said, "I modeled the output with only a current limit... no swing
bounds except for the feedback." [YOUR feedback loop]

In... Message-ID: <tvr7j7lk7esh7cuaekgtd23lsnpm0tnvcq@4ax.com

I said, "The model I'm pondering in my head takes my present basic
model..."

[My "present basic model" is not what I tried to use to fit the CAcrap
(because of its weirdness), look on my website or Google to see it.]

"with GDC, GBW, slew-rate, Rout, phase-margin, and positive and
negative swing limit specifiable... but modified as follows:

Rout => Rout-sourcing, Rout-sinking (separate values)
Current limit sourcing and sinking (separate values)
Power supply pins will reflect load _and_ quiescent currents
Output swing limits specifiable relative to rail potentials

It may even show recovery time from slamming into rails... not quite
sure yet, but I think so "

So do what you want. If you think I give a rat's ass what you do or
think, you're sadly mistaken.

...Jim Thompson

Well, I'm going to leave it there. I haven't time or inclination to argue. I
don't understand all that you have said, but I have tried to help my getting
measurements, and I do understand that a model that forever reason generates
impossible voltages is not usable. I asked you several times if you could
help with details I could use to explore the original schematic, and all you
did was give me a model that outputs more energy below its negative rail than
the input could ever feed it, and a claim that the datasheet is lying.

Now, I have no way to judge that last claim, but I do think this effort is on
a hiding to nothing, so I'm quite happy to abandon it now. Thanks for the
effort you put into it. It's good to see anyone have a go, regardless of
outcome.

Michael A. Terrell · Feb 9, 2012

"krw@att.bizzzzzzzzzzzz" wrote:

On Wed, 08 Feb 2012 18:52:10 -0800, The_Giant_Rat_of_Sumatra
GeorgeTirebiter@drmemory.org> wrote:

On Wed, 8 Feb 2012 18:21:19 -0800 (PST), Mark <makolber@yahoo.com> wrote:

Just a point. I may not have made it clear. I had the tech put in two
2way splitters and connect me to the first one. Hoping to gain 3db.
(or 4) and it did make a difference.

Where does the other leg of that splitter go to? And is that end
properly terminated?

Cable installers terminating things? You must be fucking joking.
They would have to have an IQ above 25 for that.

*WAY* above your pay grade.

Makes you wonder what they paid him for at Time Warner, if he wasn't
smart enough to install a terminator.

--
You can't have a sense of humor, if you have no sense.

Driver to drive?

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