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'[EE]'
2001\08\01@102218 by Bernard Tyers

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face
Hi all,

first post.

I am trying to use a CA3140E op-amp as a comparator.
The two inputs are chemical sensors. The difference voltage between them
can range between 400mV, to 50mV (100% concentration to 0% concentration).

I remember reading somewhere in a text book, that if V1-V2 is greater than
(I think) 100uV the op-amp will go into saturation.

Can anyone a) clarify this for me, or b)suggest a better way to measure
the difference voltage.

Component count is a factor, as is power consumption. (I want my cake and
eat it too!)

TIA
--
rgrds,
Bernard

--
Bernard Tyers*Dept. of Physical Sciences*Dublin City
University*P:01.7005273*L:N117*W:frank.physics.dcu.ie/~bty

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2001\08\01@165525 by Olin Lathrop

face picon face
> I am trying to use a CA3140E op-amp as a comparator.
> The two inputs are chemical sensors. The difference voltage between them
> can range between 400mV, to 50mV (100% concentration to 0% concentration).
>
> I remember reading somewhere in a text book, that if V1-V2 is greater than
> (I think) 100uV the op-amp will go into saturation.
>
> Can anyone a) clarify this for me, or b)suggest a better way to measure
> the difference voltage.

An opamp used as a comparator typically would go into saturation, especially
since you probably want to add a little hysterisis.  A saturated opamp may
take a little longer to respond to different input signals, but that should
still be much faster than your chemical concentration can change.


********************************************************************
Olin Lathrop, embedded systems consultant in Littleton Massachusetts
(978) 742-9014, spam_OUTolinTakeThisOuTspamembedinc.com, http://www.embedinc.com

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2001\08\02@143142 by Eisermann, Phil [Ridg/CO]

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face
       Is it possible that the statement meant "if 100uV is applied between
the inverting and non-inverting terminals, the op-amp will go into
saturation"?

       If that was the question, then someone needs to explain negative
feedback :) Certainly, it's possible to use an op-amp to amplify a
differential signal between 50mV and 400mV. Just don't apply that difference
directly to the op-amp terminals.

       Perhaps the problem needs to be explained a little more. Is the
difference between two sensors being measured? or are there two sensors,
whose ouput varies between 50mV and 400mV? What is the amplified output
connected to? what range does the output voltage need to be in?


> {Original Message removed}


'[EE]'
2002\09\22@144055 by DFansler
picon face
I started building an observatory with a roll off roof about 3 years ago.
The structure itself is finished.  The roof probably weighs about 2000 lbs
and rolls on steel wheels and while it can be pushed by hand, it takes a far
amount of force.  Not being fond of being cold, I constructed the mechanics
to roll the roof back using a couple of 24v dc motors.  The controller box
uses a 16F877 as the brains.  I am using (trying to at least) to use the PWM
to control the motors with.  The output of the PWM goes to a 220 ohm
resistor and then to the gate of an IRLZ44 (N-channel 60v 50A FET) which
between the motors and ground.  There are a pair of relays that reverse the
leads of the motors to change direction.  I am aware of back EMF and the
need for a blocking diode.  I have a blocking on each relay coil and another
diode between the +24v and the FET.  The FET works the first time, ramping
the motors up in speed, but after the relays switch the first time, the FET
becomes a dead short.  At first I thought the motors were drawing too much
current, so I tried two of the IRLZ44 paralleled - same result.  Anyone got
any suggestions?  I would really like to get this finished.

If the word pictured is not clear enough, I can place the schematic on my
web site.

Thanks to all,

David V. Fansler
.....DFanslerKILLspamspam@spam@MindSpring.com
http://www.DV-Fansler.com

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2002\09\22@192358 by Olin Lathrop

face picon face
> I started building an observatory ..

If you want a better response, try stop annoying people by:

1  -  Net setting a hard reply address so that a default reply goes to the
list instead of just you.

2  -  Put a meaningful phrase in the subject line.


*****************************************************************
Embed Inc, embedded system specialists in Littleton Massachusetts
(978) 742-9014, http://www.embedinc.com

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2002\09\22@233747 by gaston gagnon

face
flavicon
face
Olin Lathrop a écrit :

> > I started building an observatory ..
>
> If you want a better response, try stop annoying people by:
>
> 1  -  Net setting a hard reply address so that a default reply goes to the
> list instead of just you.
>
> 2  -  Put a meaningful phrase in the subject line.

Trimming is find but too much trimming is bad.
Olin, from the above how are we suppose to know who annoys you so much?
Gaston

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'[EE]'
2003\07\18@053013 by Peter Moreton
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A bit off-topic, but I'll ask anyhow: I have been asked to come up with
a vehicle 'mini-UPS' design, something that takes 12v (car DC) in and
produces 12v @3amp and 5V @6amp out. The PSU must be able to maintain
power for a few seconds when the vehicle is started, and the battery may
dip to say, 8v.

I guess I'll end up with some switcher design & and small NIMH / NICAD
battery pack able to provide a few amps to the PSU input for a minute or
so, but wonder if the listers have any thoughts on this problem? Any
great IC / regulator chips out there that solve this problem?

Thanks, Peter Moreton

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2003\07\18@104323 by Bob Axtell

face picon face
Hi Peter,

I think I'd solve the 12V dip with a NiMH. Remember that normally the car
runs at 13.8V or higher, so you could always keep a 12V NiMH pack topped
off except during starting. Since the differential is so small, I'd charge
the Pak in pulse mode, i.e. directly off the raw 13.8v using HV MOSFET
switches. For a 5V supply, there are several choices, but for ruggedness, I
like National's stepdown switchers LM2576. They are efficient and run very
cool at 3A each (I'd split the supply into 2 legs with large Schottky diodes).

Make the NiMH pak easily to replace; even with its small duty cycle, it
will need to be user-replaceable in a year or two.

Just my suggestions.

--Bob



At 10:29 AM 7/18/2003 +0100, you wrote:
{Quote hidden}

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2003\07\18@121257 by Bob Blick

face
flavicon
face
Peter Moreton said:
> A bit off-topic, but I'll ask anyhow: I have been asked to come up with
> a vehicle 'mini-UPS' design, something that takes 12v (car DC) in and
> produces 12v @3amp and 5V @6amp out. The PSU must be able to maintain
> power for a few seconds when the vehicle is started, and the battery may
> dip to say, 8v.

Sounds like a PC power supply meant for a car. Have you seen this:

http://www.bobblick.com/techref/projects/yammp3/yammp3.html

It does more than your requirements, but you can reduce it to what you
need. It'll run at 8 volts in.

Cheers,

Bob

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2003\07\18@164052 by Picdude

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face
Rather than a battery backup, why not just build a flyback or SEPIC dc-dc converter that will work from 8 to say 14V?

Cheers,
-Neil.



On Friday 18 July 2003 04:29, Peter Moreton scribbled:
{Quote hidden}

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2003\07\19@044554 by Peter Moreton

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Yes, I suppose you are right. So long as the PSU can run OK from 8v, and
produce 12v, it should withstand the sag when the vehicle is started. I
guess I need to breadboard a design and see what works.

> {Original Message removed}


'[EE]'
2004\10\15@185454 by junos (nickname)
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View/change your membership options at
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2004\10\16@152538 by Peter L. Peres

picon face


On Sat, 16 Oct 2004, junos (nickname) wrote:

> ------------------------------
>

I said no, and I meant no.
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View/change your membership options at
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'[EE]'
2004\11\15@193936 by Rich
picon face
Someone asked about single supply operation of OP AMPS a while back.  If there is still an interest in a technical review, the link below is a good one.

http://focus.ti.com/lit/an/sboa059/sboa059.pdf
___________________________________________


'[EE] '
2005\06\02@115138 by Wouter van Ooijen
face picon face
What would be the chip-of-choice to driver a bunch (4 or 8) N-Mosfets
from PIC output pins? The Mosfets are of course not 5V-types, they need
>10V at their gates.

Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu


2005\06\02@204641 by Martin K

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face
Russell McMahon posted a message in reply to a question about this
yesterday or the day before, a discrete solution (2 transistors and a
diode I believe)
For an IC solution I like the ON semiconductor drivers such as the MC33152.
Micrel has a 12A MOSFET driver in  TO-220-5 package that looks interesting.
You didn't mention what the gate charge would be or what switching
frequency is required so it is hard to give a better recommendation.

--
Martin K
http://wwia.org/

Wouter van Ooijen wrote:
> What would be the chip-of-choice to driver a bunch (4 or 8) N-Mosfets
> from PIC output pins? The Mosfets are of course not 5V-types, they need
>
>>10V at their gates.
>
>
> Wouter van Ooijen


2005\06\03@023245 by vasile surducan

picon face
On 6/2/05, Wouter van Ooijen <wouterspamspam_OUTvoti.nl> wrote:
> What would be the chip-of-choice to driver a bunch (4 or 8) N-Mosfets
> from PIC output pins? The Mosfets are of course not 5V-types, they need
> >10V at their gates.

Wouter, I suggest you an european solution: CD40107 open drain circuit
and there is also an open source but I don't remember the name, both
have two gates in a DIP8 or SO8 package, high current, high voltage
drive, with low voltage input.

Vasile


>
> Wouter van Ooijen
>
> -- -------------------------------------------
> Van Ooijen Technische Informatica: http://www.voti.nl
> consultancy, development, PICmicro products
> docent Hogeschool van Utrecht: http://www.voti.nl/hvu
>
>
> -

2005\06\03@080235 by Dennis Crawley

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face
part 1 820 bytes content-type:text/plain; (decoded 7bit)


TC426 or DS0026?

But Russell has taught me a good trick with two transistors.
Is working good with ~18Khz with 2N3904s.
The gif is made from Jinx Library(TM).:)

Dennis

vasile surducan <@spam@vsurducanKILLspamspamgmail.com> wrote:
{Quote hidden}


part 2 2398 bytes content-type:application/octet-stream; (decode)

part 3 35 bytes content-type:text/plain; charset="us-ascii"
(decoded 7bit)

2005\06\03@084020 by Russell McMahon

face
flavicon
face
> TC426 or DS0026?

> But Russell has taught me a good trick with two transistors.
> Is working good with ~18Khz with 2N3904s.
> The gif is made from Jinx Library(TM).:)

It's a good circuit. But for safety it is a very good idea to also
place a zener diode from FET gate to ground (cathode to gate).
Physically mount it as reasonably close to the FET as possible. This
shunts stops capacitively coupled transients which are injected into
the gate from the drain via the Miller capacitance. It also helps
stops gate ringing -  a whole black art in its own right. I have seen
circuits that run forever with this zener in place but die in minutes
without it. Zener voltage is slightly higher than the V+ gate drive
voltage.

For faster switching place a small capacitor in series with the base
drive resistor on the left hand transistor (not shown in your
diagram).



       Russell McMahon

2005\06\03@101105 by Herbert Graf

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face
On Fri, 2005-06-03 at 08:58 -0300, Dennis Crawley wrote:
> TC426 or DS0026?
>
> But Russell has taught me a good trick with two transistors.
> Is working good with ~18Khz with 2N3904s.
> The gif is made from Jinx Library(TM).:)
>
> Dennis

Very neat circuit.

Anyone have a similar circuit that could be used for the high side
driver in an H-Bridge running at say 200V? PMOS and NMOS high side
versions?

Thanks, TTYL

-----------------------------
Herbert's PIC Stuff:
http://repatch.dyndns.org:8383/pic_stuff/

2005\06\06@025612 by vasile surducan

picon face
On 6/3/05, Russell McMahon <RemoveMEapptechTakeThisOuTspamparadise.net.nz> wrote:
> > TC426 or DS0026?
>
> > But Russell has taught me a good trick with two transistors.
> > Is working good with ~18Khz with 2N3904s.
> > The gif is made from Jinx Library(TM).:)
>
> It's a good circuit. But for safety it is a very good idea to also
> place a zener diode from FET gate to ground (cathode to gate).
> Physically mount it as reasonably close to the FET as possible. This
> shunts stops capacitively coupled transients which are injected into
> the gate from the drain via the Miller capacitance. It also helps
> stops gate ringing -  a whole black art in its own right. I have seen
> circuits that run forever with this zener in place but die in minutes
> without it. Zener voltage is slightly higher than the V+ gate drive
> voltage.

  But also then then the 10 ohm resistor must be increased or the V+
voltage must be very carefully chosen. BTW, why such a small resistor
when the gate ON current is quite small ? How large is the gate-source
parasitic capacitance of this FET ?

Vasile

>
> For faster switching place a small capacitor in series with the base
> drive resistor on the left hand transistor (not shown in your
> diagram).
>
>
>
>        Russell McMahon
>
> -


'[EE]'
2006\04\12@190719 by moja nona
picon face


'[EE]'
2006\06\20@100942 by David VanHorn
picon face
Microsoft Robotics development kit!

http://www.pcmag.com/article2/0,1895,1978578,00.asp

http://www.microsoft.com/downloads/details.aspx?FamilyID=66d1363e-36a4-46be-ad36-01bcfbfb4969&DisplayLang=en

--
Feel the power of the dark side!  Atmel AVR

2006\06\20@143024 by Peter

picon face


On Tue, 20 Jun 2006, David VanHorn wrote:

> Microsoft Robotics development kit!
>
> http://www.pcmag.com/article2/0,1895,1978578,00.asp
>
> http://www.microsoft.com/downloads/details.aspx?FamilyID=66d1363e-36a4-46be-ad36-01bcfbfb4969&DisplayLang=en

Oh s**t. Now they embraced and extended Asimov's 3 principles of
(human-friendly) robotics.

Peter


'[EE]'
2006\09\10@061125 by YAP
picon face
Hi all,

a friend of mine is looking for two pieces of CYPRESS CY7C64513.
Anyone having two he/she want to sell (or know where to search for
them)?

Regards
/Ake


'[EE]'
2007\06\10@200501 by Carolina Dieguez
picon face
Does anyone know how to create the footprint for an electrolitic
capacitor?? Or is there some footprint standarized included in any
library I  do not know?

I really appreaciate your help and any tips you can give.

Regards,
            Carito.

2007\06\10@202159 by David VanHorn

picon face
On 6/10/07, Carolina Dieguez <spamBeGonecaro.dieguezspamBeGonespamgmail.com> wrote:
> Does anyone know how to create the footprint for an electrolitic
> capacitor?? Or is there some footprint standarized included in any
> library I  do not know?

It would probably help if you gave some idea of what cad package you are using.

2007\06\10@203932 by Carolina Dieguez

picon face
I'm  sorry, I'm using PROTEL...

On 6/10/07, David VanHorn <TakeThisOuTmicrobrixEraseMEspamspam_OUTgmail.com> wrote:
> On 6/10/07, Carolina Dieguez <RemoveMEcaro.dieguezspamTakeThisOuTgmail.com> wrote:
> > Does anyone know how to create the footprint for an electrolitic
> > capacitor?? Or is there some footprint standarized included in any
> > library I  do not know?
>
> It would probably help if you gave some idea of what cad package you are using.
> -

2007\06\10@234759 by Rich

picon face
The comment requesting the CAD package is important.  Usually, in any CAD
package you can pick a similar part and edit the part to make one with the
footprint you need.  Also, you can look at the manufacturer's packaging
specifications and dimensions and use the drawing tools to draw it and save
the file by the name you choose.


{Original Message removed}


'[EE]'
2008\01\28@132253 by Don Rahmlow
flavicon
face
I'm experimenting with analog switches/muxes ('4051 and '4066)--my first
time. When selected, the resistance of all switches is as expected, <150
ohms, but when control signal is low R varies from 20-50K among channels,
always way lower than spec. If power removed, all channels' resistance is in
spec.

My first thought was my meter, a garden-variety $20 job, but it seems to be
working fine.

Thanks all,

Don

===============
Don Rahmlow
Ramfish Golf
http://www.ramfish.com
===============


2008\01\28@150424 by PAUL James

picon face

Don,

What is the input impedance of your meter?  If it is less than 20
megohms or so, you'll load the FET down,
And you'll get less than expected resistance.  


       
Regards,

       
Jim

{Original Message removed}


'[EE]'
2008\02\10@133008 by Bill van Dijk
flavicon
face
I recently junked a Brother inkjet printer(MFC3320C), it yielded several
interesting parts. One part I like is the LCD display, a really neat and
small unit. I was hoping to use it for something else, but I can't figure
out the connections. It has wires connected to it. It has some kind of
controller chip glued on the glass, but no markings. The unite carries a
part number B53K680-1, but this seems to be a Brother part number. If I
search Google, I actually get a parts manual for the printer, but is no good
for identification.

I was wondering if anyone might have some idea what the connections might
be. I hate to chuck it.....

Bill van Dijk


'[EE]'
2011\05\23@215459 by Charles Rogers
flavicon
face
Could any one reccomend a C compiler that doesn't resort
to the Command prompt to run what ever you write.  I'm writing simple C programs and editors are easy to find but
compilers all seem to use the Command Prompt to run the
results. Thanks in advance to anyone who can help ! ! !

CR

2011\05\23@224546 by Bob Ammerman

flavicon
face
Assuming you are working in Windows:

Visual Studio 2010 C++ Express

could be a very good (and free!) choice.

-- Bob Ammerman
RAm Systems

{Original Message removed}

2011\05\24@013413 by Wouter van Ooijen

face picon face
> Could any one reccomend a C compiler that doesn't resort
> to the Command prompt to run what ever you write.  I'm
> writing simple C programs and editors are easy to find but
> compilers all seem to use the Command Prompt to run the
> results. Thanks in advance to anyone who can help ! ! !

DevCpp has a setting to develop windows applications. No experience with it, I always use it to generate commandline applications (which you for some reason seem to hate).

I am not sure what you mean by 'use the command prompt', the IDEs I know use a button to launch the application.

--
Wouter van Ooijen

-- -------------------------------------------
Van Ooijen Technische Informatica: http://www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: http://www.voti.nl/hvu

2011\05\24@020746 by Bob Blick

face
flavicon
face
On Mon, 23 May 2011 20:54 -0500, "Charles Rogers" wrote:
> Could any one reccomend a C compiler that doesn't resort
> to the Command prompt to run what ever you write.  I'm
> writing simple C programs and editors are easy to find but
> compilers all seem to use the Command Prompt to run the
> results. Thanks in advance to anyone who can help ! ! !

Are you talking about compilers for the PC or for the PIC?

Bob

-- http://www.fastmail.fm - Send your email first class

2011\05\24@020855 by Oli Glaser

flavicon
face
On 24/05/2011 02:54, Charles Rogers wrote:
> Could any one reccomend a C compiler that doesn't resort
> to the Command prompt to run what ever you write.  I'm
> writing simple C programs and editors are easy to find but
> compilers all seem to use the Command Prompt to run the
> results. Thanks in advance to anyone who can help ! ! !
>
> CR
>

Do you mean you want to create a GUI app in plain C?
If so check out Win API, Win SDK (comes with Visual Studio or can be downloaded seperately), GTK. The compiler doesn't create the GUI, it's the code you pass to it (e.g. using Windows API - CreateWindowEx() and suchlike)
Charles Petzold wrote a good book "Programming Windows" that covers the Windows API quite well IIRC.

2011\05\24@025442 by Ruben Jönsson

flavicon
face
> On Mon, 23 May 2011 20:54 -0500, "Charles Rogers" wrote:
> > Could any one reccomend a C compiler that doesn't resort
> > to the Command prompt to run what ever you write.  I'm
> > writing simple C programs and editors are easy to find but
> > compilers all seem to use the Command Prompt to run the
> > results. Thanks in advance to anyone who can help ! ! !
>
> Are you talking about compilers for the PC or for the PIC?
>
To the OP: It is not quite clear what you mean. Can you give us an example of what the compilers does and what you want it to do instead?

What do you mean by "run the results"?

Are you talking about the compiling process (writing your program) or about running your compiled program (using your program)?

/Ruben

==============================
Ruben Jönsson
AB Liros Electronic
Box 9124, 200 39 Malmö, Sweden
TEL INT +46 40142078
FAX INT +46 40947388
rubenEraseMEspam.....pp.sbbs.se
==============================

2011\05\24@064323 by Tamas Rudnai

face picon face
What do you mean by "run the results"? Run the compiled code? Most modern
IDE can run the compiled code by clicking on a button -- and then you can
get the output in a window if you like.

Or if you need a window based application (GUI as opposed to TUI/CLI), then
you also need to learn a bit of the windowing frameworks, such as MFC or
Windows Forms or VxWorks or GTK or Cocoa -- depends on your
taste, licensing policy, your base platform and whenever you need to
cross-compile your code to other platforms, and of course available tools.
Generally speaking basic stuff such as displaying a string in a text box or
handling an event like a button pressed is relatively easy in all
frameworks. However, each works differently so you cannot easily swap in
between.

Tamas



On Tue, May 24, 2011 at 2:54 AM, Charles Rogers <EraseMEcrogersspamtotelcsi.com>wrote:

> Could any one reccomend a C compiler that doesn't resort
> to the Command prompt to run what ever you write.  I'm
> writing simple C programs and editors are easy to find but
> compilers all seem to use the Command Prompt to run the
> results. Thanks in advance to anyone who can help ! ! !
>
> CR
>
>

2011\05\25@043404 by Per Linne

flavicon
face
CCS.

PerL


----- Original Message ----- From: "Charles Rogers" <RemoveMEcrogersEraseMEspamEraseMEtotelcsi.com>
To: "Microcontroller discussion list - Public." <RemoveMEpiclistspam_OUTspamKILLspammit.edu>
Sent: Tuesday, May 24, 2011 3:54 AM
Subject: [EE]


> Could any one reccomend a C compiler that doesn't resort
> to the Command prompt to run what ever you write.  I'm
> writing simple C programs and editors are easy to find but
> compilers all seem to use the Command Prompt to run the
> results. Thanks in advance to anyone who can help ! ! !
>
> CR
>
> -


'[EE]'
2012\10\08@115416 by David VanHorn
picon face
Can anyone help me?

I'm looking for a source of desktop universal input SMPSs that will do
at least 2.7A at 24V.
Those are easy to find, but the next bit isn't.

In case of overcurrent, I need the supply to shut down until the plug is pulled.
Everything I have found has "Hiccup mode" or "Auto-Restart" which is
unacceptable.
A supply that operates in this mode could cause a disastrous fire.

There are connector and ratings requirements also, but I will discuss
that with the vendor.
Surplus onesies would be interesting in that they would point me to
the proper vendor to get them from in bulk.

VERY interesting reading:
http://www.kodiakconsulting.com/page19/assets/Low%20Voltage_The%20Incompetent%20Ignition%20Source_Final.pdf

Thanks

2012\10\08@153257 by Richard Prosser

picon face
An interesting article.

I particularly liked the statement "There exists a sobering truth
about today’s electronic assemblies. 100% of today’s
consumer electronics are made without rosin flux (moisture
resistance), use fluxes that do not
“require” cleaning (leaves contamination behind more readily), use
solders that contain no lead
(creates more difficult soldering processes), and use boards that
contain no halides to prevent the
board from burning if a shorting or corrosions event were to occur."

Regarding the original posters problem - how about adding a crowbar
circuit + fuse. Pretty easy to implement on any type of power supply.

RP


On 9 October 2012 04:54, David VanHorn <RemoveMEmicrobrixTakeThisOuTspamspamgmail.com> wrote:
{Quote hidden}

>

2012\10\08@182138 by David W. McGaffney

picon face
On 10/08/2012 11:54 AM, David VanHorn wrote:
> Can anyone help me?
>
> I'm looking for a source of desktop universal input SMPSs that will do
> at least 2.7A at 24V.
> Those are easy to find, but the next bit isn't.
>
> In case of overcurrent, I need the supply to shut down until the plug is pulled.
> Everything I have found has "Hiccup mode" or "Auto-Restart" which is
> unacceptable.
> A supply that operates in this mode could cause a disastrous fire.
>
> There are connector and ratings requirements also, but I will discuss
> that with the vendor.
> Surplus onesies would be interesting in that they would point me to
> the proper vendor to get them from in bulk.
>
> VERY interesting reading:
> http://www.kodiakconsulting.com/page19/assets/Low%20Voltage_The%20Incompetent%20Ignition%20Source_Final.pdf
>
> Thanks!
Why not add a SCR that fires when it reaches a certain current limit...It would "lock"/crowbar the output until the power supply has been unplugged and the SCR's gate releases. Reading the voltage developed across a low value (.5ohm) high wattage  (5~10W) resistor in series with the 24v leg and firing the gate of the SCR when it reaches your current limit... A few components and a standard (available) 24v SMPS power supply. You would need to handle the turn on surge also.
Dav

2012\10\08@215226 by David VanHorn

picon face
All good suggestions, IF I could modify the existing circuits.

What I need, is a power supply brick, to replace the existing power
supply brick, that won't keep hammering a failed circuit


'[EE]'
2013\11\05@164203 by George OConner
picon face
hello,
    please forgive my very beginner question, but i was wondering how to
post a question??..i am new to this forum.

george
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2013\11\05@170736 by Joe Wronski

flavicon
face
Well,you just *did* post a question. You can even put t he question or a summary of it in the subject line, right after the tag [EE] or [$WHATEVER]

On 11/5/2013 4:42 PM, George OConner wrote:
> hello,
>       please forgive my very beginner question, but i was wondering how to
> post a question??..i am new to this forum.
>
> george


-- Joe Wronski
EraseMEjwronskispamspamspamBeGonestillwatereng.net
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2013\11\05@171622 by George OConner

picon face
Joe,
   sweet!!..i guess that was my next question..did this work??..lol
well, thank you and i look forward to being a member on this forum..great
day!!

George


On Tue, Nov 5, 2013 at 3:10 PM, Joe Wronski <RemoveMEjwronskiKILLspamspamstillwatereng.net>wrote:

{Quote hidden}

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2013\11\05@193231 by Joe Wronski

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Great!
I forgot to put a disclaimer, so I'll add one now:

<disclaimer>I am relatively new here.  Others have much more knowledge and some carry some power.  You'll get to know them in time. </disclaimer>

Sure has been quiet lately.
Joe

On 11/5/2013 5:16 PM, George OConner wrote:
{Quote hidden}

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'[EE]'
2015\05\16@165335 by John Coppens
flavicon
face
On Fri, 3 Apr 2015 00:33:29 -0400
Sean Breheny <@spam@shb7@spam@spamspam_OUTcornell.edu> wrote:

> but another possibility is that it is your eye

.... and a variant: Maybe the spark's direction at the 'hotspot' is directly
towards or away from you. In that case, the intensity would he higher too.

John
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'[EE]'
2016\01\09@091213 by John Coppens
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face
On Mon, 07 Dec 2015 13:23:07 -0800
Bob Blick <spamBeGonebobblickspamKILLspamftml.net> wrote:

> I'll look again tonight and try to take a picture or two.

This is probably outdated, but maybe it helps someone.

I've been surprised how an electronic flash makes markings appear -
even the faintest laser markings. So, even if the camera doesn't
need/propose flash, still enable it...

John
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2016\01\09@100922 by Allen Mulvey

flavicon
face
Adding more light allows the use of a smaller aperture.
This, in turn, gives greater depth of field which makes more
things appear sharp. This is especially noticeable when the
camera is close to the subject.

Allen

> {Original Message removed}

2016\01\09@182040 by RussellMc

face picon face

John-Bob said:
> I've been surprised how an electronic flash makes markings
> appear - even the faintest laser markings. So, even if the camera
> doesn't need/propose flash, still enable it...


On 10 January 2016 at 04:11, Allen Mulvey <.....allenspam_OUTspamamulvey.com> wrote:

> Adding more light allows the use of a smaller aperture.
> This, in turn, gives greater depth of field which makes more
> things appear sharp. This is especially noticeable when the
> camera is close to the subject.
>
>
​As well as that, flash adds very directional light (unless an effective
diffuser is used)(which is not anted in this case)  and throws shadows even
within small features which helps increase their contrast.


Russell

​


> Allen
>
> > {Original Message removed}


'[EE]'
2016\04\24@161106 by John Coppens
flavicon
face
On Sun, 24 Apr 2016 13:32:39 -0400
Jason White <TakeThisOuTwhitewaterssoftwareinfo.....spamTakeThisOuTgmail.com> wrote:

> (1) A 2N7002 often is rated for a "typical" Drain-Source leakage current of
> 1 micro-amp when 60 volts is across it a room temperature. Will this
> leakage current decrease if the applied voltage is lower?
>
> (1b) Is it possible to extrapolate how much lower the current would be at a
> lower Vds voltage?

Not really - and surely it's not linear. I also believe that the 1uA is
very probably an extreme value, probably at the max temperature, etc.
'Normal" transistors will be very much lower... But it would be unwise to
rely on that...

> (2) Would placing multiple MOSFETs in series reduce the Drain-Source
> leakage current? (Of course, then gate leakage current may start becoming a
> factor.)

Placing several FETs in series will  reduce the leakage current somewhat,
but mainly because the voltage is reduced. But it'll introduce other
problems - you'd have to distribute the voltage evenly, which would involve resistors, just what you don't want. And you'll increase the Ron.

Ever consider analog switches? The old CD4066 can switch 15 V, and has a
rating of 0.1nA Typ., at 25°C. A slightly more sophisticated switch
will surely do much better.

John

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'[EE]'
2016\06\29@132821 by Van Horn, David
flavicon
face
I will be visiting in the Shenzen area in China in August.

Are there any special things I might want to check out?

--
David VanHorn
Lead Hardware Engineer

Backcountry Access, Inc.
2820 Wilderness Pl, Unit H
Boulder, CO  80301 USA
phone: 303-417-1345  x110
email: TakeThisOuTdavid.vanhornKILLspamspamspambackcountryaccess.com<.....david.vanhornspamRemoveMEbackcountryaccess.com>

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2016\06\29@224842 by RussellMc

face picon face
On 30 June 2016 at 05:28, Van Horn, David <
RemoveMEdavid.vanhornspamspamBeGonebackcountryaccess.com> wrote:

> I will be visiting in the Shenzen area in China in August.
>
> Are there any special things I might want to check out?
>
> Legion.
Remind me "later"
.....

Do tell us why and how long.
Staying where? - I can recommend an adequate and lowish cost hotel (but
there are thousands)


Russell
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2016\06\29@230921 by David VanHorn

picon face
Work. Two weeks this time.  They are setting up hotel etc.
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'[EE]'
2016\07\03@202114 by V G
flavicon
face
The respirator store, the isle where the P99 ones are located.

On Wed, Jun 29, 2016 at 1:28 PM, Van Horn, David <
spamBeGonedavid.vanhorn@spam@spamspam_OUTbackcountryaccess.com> wrote:

> I will be visiting in the Shenzen area in China in August.
>
> Are there any special things I might want to check out?
>
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2016\07\05@082914 by Van Horn, David

flavicon
face
I must have missed something.

-----Original Message-----
From: TakeThisOuTpiclist-bouncesspamspammit.edu [piclist-bouncesEraseMEspammit.edu] On Behalf Of V G
Sent: Sunday, July 3, 2016 6:21 PM
To: Microcontroller discussion list - Public.
Subject: Re: [EE]

The respirator store, the isle where the P99 ones are located.

On Wed, Jun 29, 2016 at 1:28 PM, Van Horn, David < RemoveMEdavid.vanhornEraseMEspamspam_OUTbackcountryaccess.com> wrote:

> I will be visiting in the Shenzen area in China in August.
>
> Are there any special things I might want to check out?
>
--
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2016\07\05@142228 by Bob Blick

flavicon
face
August air pollution in Shenzen :)
________________________________________
From: @spam@piclist-bouncesRemoveMEspamEraseMEmit.edu <EraseMEpiclist-bouncesspam@spam@mit.edu> on behalf of Van Horn, David <@spam@david.vanhornspam_OUTspam.....backcountryaccess.com>
Sent: Tuesday, July 5, 2016 5:29 AM
To: Microcontroller discussion list - Public.
Subject: RE: [EE]

I must have missed something.

{Original Message removed}

2016\07\05@144442 by Van Horn, David

flavicon
face
Oh.  :(  
Last year I was hospitalized 3x for what we thought was a bacteria/virus/demon in my lungs, but it turned out to be acute irritation caused by an ultrasonic humidifier putting mineral dust in the air.

At one point, I was down to 70% O2 after three hours exposure.

Not sure how to evaluate the risk level.

{Original Message removed}

2016\07\05@151507 by John Gardner

picon face
....70% O2...

Not much fun...  :(
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2016\07\05@152810 by V G

flavicon
face
On Tue, Jul 5, 2016 at 2:44 PM, Van Horn, David <
spamBeGonedavid.vanhornEraseMEspambackcountryaccess.com> wrote:

> Oh.  :(
>
> Last year I was hospitalized 3x for what we thought was a
> bacteria/virus/demon in my lungs, but it turned out to be acute irritation
> caused by an ultrasonic humidifier putting mineral dust in the air.
>
> At one point, I was down to 70% O2 after three hours exposure.
>
> Not sure how to evaluate the risk level


Ouch! That's why I use a large evaporative humidifier in the winter and a
HEPA air filter all the time. After a couple of weeks, the wick turns into
a disgusting yellow-brown colour from all the minerals in the water.

But if you have sensitive lungs, I'd strongly suggest you get one of these:
https://www.amazon.com/3M-Facepiece-Respirator-6291-Particulate/dp/B000FTEDMM/ref=sr_1_3?ie=UTF8&qid=1467746622&sr=8-3&keywords=3m+respirator

They're cheap, comfortable, and absolutely amazing. I have sensitive lungs
and I use those if the air quality around me drops. The difference is
immediately noticeable after you put it on.
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2016\07\05@172026 by James Cameron

flavicon
face
Oh, you used a ground water supply.  I've only got rain water.  I
figure it has already passed the breathability requirements.  ;-)

On Tue, Jul 05, 2016 at 06:44:39PM +0000, Van Horn, David wrote:
> Oh.  :(  
>
> Last year I was hospitalized 3x for what we thought was a bacteria/virus/demon in my lungs, but it turned out to be acute irritation caused by an ultrasonic humidifier putting mineral dust in the air.
>
> At one point, I was down to 70% O2 after three hours exposure.
>
> Not sure how to evaluate the risk level.
>
> {Original Message removed}

2016\07\25@125331 by John Coppens

flavicon
face
On Sat, 23 Jul 2016 19:52:21 -0500
BOB <bobscncspamBeGonespamcharter.net> wrote:

> I have worked on air compressors in industrial inviorment for over 45 years.

The compressor I have is 25 litres, which is, I believe, around 6 or 7 gallons. Not professional material at all.

It has three functions
- power switch, which can be activated manually

- The power switch is also activated when the compressor reaches it's max pressure

- When the switch is activated by either action, it also releases the pression in
the tubing, to avoid having too much pressure on the pump on restarting.

As I mentioned in the original mail, the switch popped out by itself,
reactivating the motor.
I was trying to determine _what_ was the cause... and yes, I found
loads of offers on the net, and with the state_subsided mail from
China, those things are _really_ cheap. Still, adding import taxes, the
delay (30-60 days for 'free shipment'), and customs bureaucracy, the
real cost is far from that.

And the engineer in me wanted to know more ;-)

So, yesterday I dismantled the switch, and found out that the
pushbutton was supposed to have two 'stable' states: a circular
arrangements of 8 plastic springs press on the button's axis and a
pattern in its thickness provides positive in-or-out action.
I suspect that usage caused the springs to wear down, and the
pressure wasn't enough anymore to keep the button down. The
pressure wasn't even enough to keep the button in the switch.
Anyway, I made a quick replacement in the lathe, and I'll be
sure to put some grease to avoid wear.

Thanks all!
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'[EE]'
2019\01\23@103102 by David Van Horn
flavicon
face
Here's an odd question:   Take a common P Fet, in this case an AO3435 from Alpha and Omega.
Ground the drain. (Actually connected to a small winding on a transformer, but <<1 ohm DC path to ground)
Connect the source to ground through 47k
Connect the gate to the source through 100k.
Connect a 100uF capacitor to the source and ground.

Is the FET on, or off in this condition?

My expectation is that the FET is off, and only parasitic capacitances connect the 100uF on the source lead to the drain lead.


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2019\01\23@124900 by RussellMc

face picon face
On Thu, 24 Jan 2019 at 04:31, David Van Horn <
RemoveMEdavid.vanhorn@spam@spamspamBeGonebackcountryaccess.com> wrote:

> Here's an odd question:   Take a common P Fet, in this case an AO3435 from
> Alpha and Omega.
> Ground the drain. (Actually connected to a small winding on a transformer,
> but <<1 ohm DC path to ground)
> Connect the source to ground through 47k
> Connect the gate to the source through 100k.
> Connect a 100uF capacitor to the source and ground.
>
> Is the FET on, or off in this condition?
>
> If the transformer has AC on it:

On Vtransformer = Vt = Vdrain positive excursion > 1 diode drop, Csg will
charge positive via FET body diode.

On Vt < gnd excursions, Millar capacitance Cdg may drive gate negative
relative to source depending on gate voltage slew rate compared to gate
time constant (Cgs.Rgs + C...)

So FET may turn on part way into negative cycles and discharge C100uF until
source tends to assymptote towards drain by Vgsth, but period is also
dependant on gate time constant.

it turn on blips or maybe long on's part way through negative drain
transitions.

Needed: Waveform on drain - frequency , voltage , shape.

        Russell
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2019\01\23@125619 by RussellMc

face picon face
On Thu, 24 Jan 2019 at 04:31, David Van Horn <
.....david.vanhorn@spam@spamEraseMEbackcountryaccess.com> wrote:

> ...:   Take a common P Fet, in this case an AO3435 from Alpha and Omega.
>

Datasheet ref always useful

        http://aosmd.com/res/data_sheets/AO3435.pdf

Vgsth ~= 1V.

Ciss~= 500 / 750 pF  typ/max


R
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'[EE]'
2019\06\04@081522 by David Van Horn
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face
Output pin voltage on PIC24FJ128GA306T-I/PT

The data sheet uses 3.6V as VCC, and specifies a 3mA load, neither of which is true in my application.
VCC is 3.3V, and the I/O pin load is a 1uA leakage current from a logic gate.

What's the minimum I can expect for a logic high output voltage under these circumstances?

--
David VanHorn
Lead Hardware Engineer

Backcountry Access, Inc.
2820 Wilderness Pl, Unit H
Boulder, CO  80301 USA
phone: 303-417-1345  x110
email: .....david.vanhornRemoveMEspambackcountryaccess.com<.....david.vanhornSTOPspamspam@spam@backcountryaccess.com>

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2019\06\04@084707 by Jim

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David,

Without testing any of this, I would say you could expect very close to
3.3V.
As long as the VoH is higher than 2.4V for TTL, or 2.64 in your 3.3V
case for CMOS, you should be okay.
Again, this is just theoretical based on the very low load.  Really,
the only way to get an accurate  value is to measure it under actual operating conditions.


Regards,

Jim

> ---{Original Message removed}

2019\06\04@114900 by David Van Horn

flavicon
face
I hear ya, but I don't want to commit based on a few samples from one production lot. Is there any doc from uChip that would support this?

--
David VanHorn
Lead Hardware Engineer

Backcountry Access, Inc.
2820 Wilderness Pl, Unit H
Boulder, CO  80301 USA
phone: 303-417-1345  x110
email: david.vanhornEraseMEspam@spam@backcountryaccess.com 

{Original Message removed}

2019\06\04@161524 by Jim

flavicon
face


Not to my knowledge, but then again, I don't know what is and isn't out
there from manufacturers, users, testers, etc.

Regards,

Jim

{Quote hidden}

> {Original Message removed}

2019\06\04@194847 by RussellMc

face picon face
Datasheet here

   http://ww1.microchip.com/downloads/en/DeviceDoc/30009996g.pdf

DS is unsurprisingly silent on this.
(p359 on)

I'd EXPECT it to be within half a whisper of Vdd, but ... .

Adding a large value pullup would (may) assist if highness matters.
You knew that.

                 Russell

>
>
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2019\06\05@074744 by David Van Horn

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Agreed on both counts, but I'm reluctant to move forward without something in writing.
I could measure hundreds of chips, but that says little about the next batch.

--
David VanHorn
Lead Hardware Engineer

Backcountry Access, Inc.
2820 Wilderness Pl, Unit H
Boulder, CO  80301 USA
phone: 303-417-1345  x110
email: spamBeGonedavid.vanhorn@spam@spambackcountryaccess.com 

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2019\06\05@101402 by Kerry

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Take the scientific approach.

The ON resistance of the output FET is (VCC - VOUT) / IOUT.  The data
sheet uses 3.6V as VCC, and specifies a 3mA load. Say the output voltage
is specified as 3.3V.  The FET on resistance would be .3V/.003A = 100
Ohms.  At VCC = 3.3V and 1 uA load, output voltage would be 3.3V -
(.000001 A * 100 Ohms) = 3.299V

Kerry


On 6/5/2019 7:47 AM, David Van Horn wrote:
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2019\06\05@130003 by David Van Horn

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Agreed, but that assumes that the output fets are really linear resistors at this operating point.
I believe that is true, but I don't know it to be true.


--
David VanHorn
Lead Hardware Engineer

Backcountry Access, Inc.
2820 Wilderness Pl, Unit H
Boulder, CO  80301 USA
phone: 303-417-1345  x110
email: spamBeGonedavid.vanhornspam_OUTspamRemoveMEbackcountryaccess.com 

{Original Message removed}

2019\06\05@162516 by Kerry

flavicon
face

I think, therefor I am.  All else is speculation and supposition.

It is starting to sound like 1 of 3 things:
  1)  You are playing some sort of a game with us.
  2)  You are on the verge of a nervous breakdown.
  3)  You are 2/3 of the way through reading "Zen and the Art of
Motorcycle Maintenance"



On 6/5/2019 12:59 PM, David Van Horn wrote:
{Quote hidden}

> {Original Message removed}

2019\06\05@163918 by David Van Horn

flavicon
face

No game..  

Check the web site.  Our products are not toys.  If they don't work, people die. Absolutely zero exaggeration there.  ZERO tolerance for hobby hacks.

That said, I need to find economical solutions.  If I don't need extra parts to make this work then I'm very happy.  If I know I can't get there and be 100% inside data sheet specs with all component tolerances accounted for then that justifies whatever extra glue is needed.  But I need to know one way or the other.     At the moment, I'm leaning toward the glue simply because I can't find enough supporting docs to say "this works and I can bet my life on it.".
I have to guarantee functionality under all spec'd operational conditions.  

If I won't bet my life on this product, why should you?

Never read the book, but I've been tempted several times.

I'm just hoping someone knows of an app note or similar that I can reference one way or the other.  


--
David VanHorn
Lead Hardware Engineer

Backcountry Access, Inc.
2820 Wilderness Pl, Unit H
Boulder, CO  80301 USA
phone: 303-417-1345  x110
email: david.vanhornspam@spam@backcountryaccess.com 

{Original Message removed}

2019\06\05@170600 by Forrest Christian (List Account) n/a

flavicon
face
It sounds like you haven't been assigned a FAE by microchip.

If not, I'd call microchip sales, and ask/demand to be assigned a FAE.
 There's one that covers your area, guaranteed.   My experience is
that they don't automatically assign these to smaller customers but
will if asked - I have one and I only consume around 4-5K pcs of
microchip products (around 2K of which are processors) per year.

Tell the FAE what you're wanting to know - and they'll contact the
factory and get you a real answer quite possibly from the person who
designed it.

I'd also highly recommend attending microchip masters in Arizona in
august.   It will change the way you interact with microchip in a
positive way, guaranteed.


On Wed, Jun 5, 2019 at 3:47 PM David Van Horn
<EraseMEdavid.vanhornRemoveMEspamSTOPspambackcountryaccess.com> wrote:
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2019\06\05@171858 by David Van Horn

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Actually, Masters is on my roadmap if nothing pops up and eats my time.
Nope, we haven't needed anything beyond the data sheet up to this point, but I'm trying to validate a corner case in a new design.
--
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2820 Wilderness Pl, Unit H
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2019\06\05@172204 by David Van Horn

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" If it's life critical, doing anything the manufacturer doesn't recommend would tend to be viewed as negligent"

Exactly.  The corner case I'm trying to resolve is not covered by the data sheet.
Microchip knows who we are and what we do.  We've been using them for a LONG time.

" and you want to be rather creative with certainty.   "  I take offence at this statement.   I am looking for documentation that will either establish that what I'm attempting is in spec, or is not in spec.  If not, then I can justify the cost of the additional glue.  If it's in spec, then I will have the documentation to back it up.   How do you see this as "rather creative"?



--
David VanHorn
Lead Hardware Engineer

Backcountry Access, Inc.
2820 Wilderness Pl, Unit H
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phone: 303-417-1345  x110
email: RemoveMEdavid.vanhornspam_OUTspambackcountryaccess.com 

{Original Message removed}

2019\06\05@180443 by Kerry

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I confess that I didn't bother to actually check the data sheet before
responding, I just assumed that 3.3V was within the specified range of
VCC.  Now I have checked the data sheet, and VCC is specified as 2.0 to
3.6V.  That is why I don't understand your concern about running on
3.3V, or why you call in a "hobby hack".  You can't possibly expect a
data sheet to list every parameter for every possible VCC value from 2.0
to 3.6V and every output current from 1uA to 3mA.  It would be the size
of an encyclopedia.

Is there something going on that you're not telling us?

Kerry


On 6/5/2019 4:38 PM, David Van Horn wrote:
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2019\06\05@184004 by Isaac M. Bavaresco

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By the datasheet, the Rds(on) of the high-side FETs is very stable, for
every VCC (above and below 3.3 V) and output current listed it is 200 Ohm,
except for VCC=2.0 V an Ioh=1 mA, which it has a Rds(on) of 350 Ohm.

So it is safe to assume that Rds(on) for VCC= 3.3 V is not below 200 Ohm.

Em qua, 5 de jun de 2019 11:16, Kerry <spam_OUTkwentworthspam_OUTspamspam_OUTskunkworksnh.com>
escreveu:

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2019\06\05@212913 by Stephen Forrest

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Hi David -

I understand your abundance of caution. Here's my take:

If I understand, you are loading a PIC output with logic gate that has an
input leakage current of 1 uA (microamp to be sure). Vdd for the system is
3V3. The datasheet in table 32.9 param. DO20 gives 4 data points for Vout.
The one you referenced was for Vcc = 3V6 and Iout = 3mA (milliamp to be
sure). Plot Vdd-Vout for ALL four points and then consider 0 amps load (no
D/S value so be as liberal as you like for worst case...). Fit curves to
each set then plot YOUR conditions.

PIC's are CMOS devices. The output structures are CMOS FETs (with
protection diodes) (an FAE can verify if in question), so Vds *will* reduce
as Ids reduces. Not linear but almost certainly monotonically. Vout for the
PIC I/O is then Vdd-Vds (with some variation for leakage current). I'm sure
you will be able to draw valid conclusions.

I have made some assumptions, so not all datasheet backed (datasheets are
subject to change anyway) but I have applied my professional training,
experience and judgment in those assumptions. My take is you'll be fine but
"document and peer review"...

Stephen


On Thu, Jun 6, 2019 at 7:24 AM David Van Horn <
RemoveMEdavid.vanhornKILLspamspam@spam@backcountryaccess.com> wrote:

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2019\06\05@213901 by Isaac M. Bavaresco

picon face
Oops...

....not higher than 200 Ohm...

Em qua, 5 de jun de 2019 19:41, Isaac M. Bavaresco <KILLspamisaacbavarescospam.....gmail.com>
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2019\06\06@043032 by AB Pearce - UKRI STFC

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I would agree with Kerry. What is it you are attempting to do that requires you to be so sure of how close you can get to the rail voltage at such low currents?

You are talking in terms of a digital output, so the next input in line is going to see it as either a 1 or a 0, unless the next device in line is being run at the extremes of its operating characteristics.

If the high voltage is so critical why can you not run the micro at 3.4V Vcc to ensure you are reaching the voltage you need?


{Original Message removed}

2019\06\06@100129 by David Van Horn

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There are many things I am concealing.  However, I have provided all necessary information.
I am simply looking for any other information that would definitely answer the question of the guaranteed output voltage when the I/O pin is loaded as described, a few pF for the gate and 1uA leakage, which for this problem I would assume is to ground (worst case) rather than up which would help me.

Sorry, but I'm not conducting a design review on a public forum.  

I was hoping there was an app note, or other document outside the part data sheet.

--
David VanHorn
Lead Hardware Engineer

Backcountry Access, Inc.
2820 Wilderness Pl, Unit H
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phone: 303-417-1345  x110
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{Original Message removed}

2019\06\06@100459 by David Van Horn

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I agree that would solve my problem, but for reasons which are proprietary and too complicated to get into without an NDA, that option is not open to me.

--
David VanHorn
Lead Hardware Engineer

Backcountry Access, Inc.
2820 Wilderness Pl, Unit H
Boulder, CO  80301 USA
phone: 303-417-1345  x110
email: david.vanhornspamspambackcountryaccess.com 

{Original Message removed}

2019\06\06@100608 by David Van Horn

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"document and peer review"...

Exactly.  I believe, for exactly the same reasons, that this is completely fine, but I cannot in good conscience rely on that in this application. For most of the other products I've designed over the years, I'd be 100% confident that it would work whether we built 1 or 10,000,000. (Been both places, done both)
I take these designs VERY seriously.
The data sheet simply gives no hard information on the unloaded case.

--
David VanHorn
Lead Hardware Engineer

Backcountry Access, Inc.
2820 Wilderness Pl, Unit H
Boulder, CO  80301 USA
phone: 303-417-1345  x110
email: RemoveMEdavid.vanhornspamBeGonespamRemoveMEbackcountryaccess.com 

{Original Message removed}

2019\06\06@115143 by Bob Blick

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Hi David,
That pin will be noisy as heck and also mostly follow the internal V+ inside the chip, so it will vary depending on the instantaneous current drain of the entire chip, expect 200 millivolts or more, peak-to-peak. Even if you heavily filter the output,  I wouldn't trust it to be closer than 20 millivolts from the Vcc pin voltage.
Best regards, Bob
P.S. Now that Microchip = Atmel you're using PICs again???? :)
________________________________________
From: KILLspampiclist-bouncesspamBeGonespammit.edu <@spam@piclist-bouncesSTOPspamspam@spam@mit.edu> on behalf of David Van Horn Sent: Tuesday, June 4, 2019 5:14 AM
To: Microcontroller discussion list - Public.
Subject: [EE]

Output pin voltage on PIC24FJ128GA306T-I/PT

The data sheet uses 3.6V as VCC, and specifies a 3mA load, neither of which is true in my application.
VCC is 3.3V, and the I/O pin load is a 1uA leakage current from a logic gate.

What's the minimum I can expect for a logic high output voltage under these circumstances?

--
David VanHorn
Lead Hardware Engineer


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2019\06\06@160852 by David Van Horn

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P.S. Now that Microchip = Atmel you're using PICs again???? :) ________________________________________

It wasn't my choice. 😊  
Can't say much more.

Pics have come a LONG way since '98.  Since then I've been mostly AVR, picked up ARM about 8 years ago, and Nordic devices.
There's always new stuff on the horizon.

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2019\06\09@004418 by Stephen Forrest

picon face

How about just loading the pin into the documented area, such that I(load)
>> I(leakage) of the next part ;o)

Let me guess - battery powered?

S.


On Fri, Jun 7, 2019 at 6:11 AM David Van Horn <
david.vanhornspamBeGonespamspamBeGonebackcountryaccess.com> wrote:

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2019\06\09@005104 by RussellMc

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On Sun, 9 Jun 2019 at 16:47, Stephen Forrest <spamBeGonesforrest.auspamgmail.com> wrote:


> Let me guess - battery powered?
>
> Most (but not all) avalanches are a fair way away from mains power.


        R
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2019\06\10@074910 by David Van Horn

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Indeed.  And usually in low temperatures. 😊

--
David VanHorn
Lead Hardware Engineer

Backcountry Access, Inc.
2820 Wilderness Pl, Unit H
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phone: 303-417-1345  x110
email: spam_OUTdavid.vanhornSTOPspamspambackcountryaccess.com 

{Original Message removed}

2019\06\10@075159 by David Van Horn

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FWIW, since I can't scare up any definitive documentation, I'm engaging support from Microchip.


--
David VanHorn
Lead Hardware Engineer

Backcountry Access, Inc.
2820 Wilderness Pl, Unit H
Boulder, CO  80301 USA
phone: 303-417-1345  x110
email: RemoveMEdavid.vanhornspamspambackcountryaccess.com 

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'[EE]'
2019\12\17@135353 by David Van Horn
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A hopefully quick question:

I have a system where I need to use the same connection for debug/programming and for serial comms.
Is it possible to damage any of the uChip official programmers (PM3- PICKit etc) if the pic is asserting that pin and the programmer is trying to drive it opposite?

--
David VanHorn
Lead Hardware Engineer

Backcountry Access, Inc.
2820 Wilderness Pl, Unit H
Boulder, CO  80301 USA
phone: 303-417-1345  x110
email: TakeThisOuTdavid.vanhornspamspamRemoveMEbackcountryaccess.com<KILLspamdavid.vanhornspamspamspam_OUTbackcountryaccess.com>

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2019\12\17@141151 by Isaac M. Bavaresco

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David,

The programmer will assert !MCLR before doing any programming, so the pins
will be in high impedance state.

Microchip's programmers/debuggers are very well protected and can withstand
a lot of abuse, even reverse polarity.

Cheers,
Isaac

Em ter, 17 de dez de 2019 15:55, David Van Horn <
david.vanhornRemoveMEspambackcountryaccess.com> escreveu:

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'[EE]'
2020\06\08@175158 by Harold Hallikainen
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High currents and "sharp edges" make minor inductances significant. I'd be
tempted to use a protoboard with a solid ground plane and some adhesive
backed copper strap for the fast high current portions of the circuit.

Harold

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2020\06\28@180433 by madscientistatlarge n/a

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Is it at all reasonable to build a switching power supply on a perf board?  I plan to use heavy gauge wire and properly fix the location of all components.  This would be a variable (digital programming) buck converter.  Current will be about 10A max, usually less.  Output noise and somewhat poor regulation are acceptable to me in this case.  Obviously I'd also be running it at 10's of kilohertz as well to mitigate some of the concerns.  Is it reasonable if I use a proto-board with a ground plane?  I know this is usually somewhat problematic.  Thanks.


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2020\06\28@182529 by Bob Blick

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Probably be better than most of the cheap buck converter modules from eBay/Aliexpress.

Remember, any switching regulator needs to have output ripple in order to regulate. Otherwise how would you control the duty cycle of the switch? If you need low ripple, you must use a secondary filter.

Cheers, Bob

________________________________________
From: EraseMEpiclist-bouncesRemoveMEspammit.edu <spampiclist-bounces.....spamspammit.edu> on behalf of madscientistatlarge Sent: Sunday, June 28, 2020 3:03 PM
To: piclistspam_OUTspam@spam@mit.edu
Subject: [EE]

Is it at all reasonable to build a switching power supply on a perf board?  I plan to use heavy gauge wire and properly fix the location of all components.  This would be a variable (digital programming) buck converter.  Current will be about 10A max, usually less.  Output noise and somewhat poor regulation are acceptable to me in this case.  Obviously I'd also be running it at 10's of kilohertz as well to mitigate some of the concerns.  Is it reasonable if I use a proto-board with a ground plane?  I know this is usually somewhat problematic.  Thanks.



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2020\06\28@182949 by Jason White

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Absolutely! The key is planning out the component placement and signal
routing. As long as the design (schematic, etc.) is good, a hand-wired
circuit operating at 10s or even 100s of kHz on perfboard is perfectly
reasonable.

In the amateur radio community its common to see this style of construction
up into the 10MHz range.

On Sunday, June 28, 2020, madscientistatlarge <
.....madscientistatlargespamspam.....protonmail.com> wrote:

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2020\06\29@114951 by David Van Horn

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Yup.  Manhattan style is probably better than perfboard here.

________________________________
From: piclist-bouncesKILLspamspamEraseMEmit.edu <EraseMEpiclist-bounces@spam@spam@spam@mit.edu> on behalf of Harold Hallikainen <@spam@haroldspamspamKILLspammai.hallikainen.org>
Sent: Sunday, June 28, 2020 4:51 PM
To: Microcontroller discussion list - Public. <spamBeGonepiclistRemoveMEspamEraseMEmit.edu>
Subject: Re: [EE]

High currents and "sharp edges" make minor inductances significant. I'd be
tempted to use a protoboard with a solid ground plane and some adhesive
backed copper strap for the fast high current portions of the circuit.

Harold

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'[EE]'
2020\07\02@185405 by madscientistatlarge n/a
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What is "Manhattan style"?  I've heard of "dead bug" style over copper clad, but not "Manhattan".  I'm always looking for clever ways to do things.  I had already planed on using copper strip on the high current loops.  I'll definitely be using a 2 stage filter on the output and at least one stage on the input.


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On Monday, June 29, 2020 9:48 AM, David Van Horn <TakeThisOuTdavid.vanhornspambackcountryaccess.com> wrote:

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2020\07\02@185711 by Byron Jeff

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www.sdmakersguild.org/the-art-of-manhattan-style-circuit-construction/

Talks about Manhattan, dead bug, live bug too.

BAJ

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2020\07\02@191911 by madscientistatlarge n/a

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Thank you!  Very good information.  I'd also considered the Live bug approach, specifically for chips that need a thermal pad under the chip.  I've used a lot of the tricks mentioned, but it's good to know what they are called and how others have been clever.


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