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5V 200mA LDO with 0.5% accuracy

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  5V 200mA LDO with 0.5% accuracy Winfield Hill <hill@rowland.harvard.edu> - 2016-11-03 18:52 -0700
    Re: 5V 200mA LDO with 0.5% accuracy bill.sloman@ieee.org - 2016-11-03 20:05 -0700
    Re: 5V 200mA LDO with 0.5% accuracy Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> - 2016-11-03 23:06 -0400
      Re: 5V 200mA LDO with 0.5% accuracy Winfield Hill <hill@rowland.harvard.edu> - 2016-11-04 06:34 -0700
        Re: 5V 200mA LDO with 0.5% accuracy speff <spehro@gmail.com> - 2016-11-04 13:46 -0700
    Re: 5V 200mA LDO with 0.5% accuracy TTman <pcw1.cad@ntlworld.com> - 2016-11-04 13:24 +0000
      Re: 5V 200mA LDO with 0.5% accuracy Winfield Hill <hill@rowland.harvard.edu> - 2016-11-04 06:43 -0700
        Re: 5V 200mA LDO with 0.5% accuracy TTman <pcw1.cad@ntlworld.com> - 2016-11-04 20:06 +0000
      Re: 5V 200mA LDO with 0.5% accuracy Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2016-11-07 09:07 -0500
    Re: 5V 200mA LDO with 0.5% accuracy Boris Mohar <borism_void_@sympatico.ca> - 2016-11-04 09:25 -0400
      Re: 5V 200mA LDO with 0.5% accuracy Winfield Hill <hill@rowland.harvard.edu> - 2016-11-04 06:53 -0700
    Re: 5V 200mA LDO with 0.5% accuracy David Brown <david.brown@hesbynett.no> - 2016-11-04 14:44 +0100
      Re: 5V 200mA LDO with 0.5% accuracy whit3rd <whit3rd@gmail.com> - 2016-11-04 11:51 -0700
    Re: 5V 200mA LDO with 0.5% accuracy John Larkin <jjlarkin@highlandtechnology.com> - 2016-11-04 08:23 -0700
      Re: 5V 200mA LDO with 0.5% accuracy George Herold <gherold@teachspin.com> - 2016-11-04 08:33 -0700
        Re: 5V 200mA LDO with 0.5% accuracy John Larkin <jjlarkin@highlandtechnology.com> - 2016-11-04 08:50 -0700
          Re: 5V 200mA LDO with 0.5% accuracy Jeroen Belleman <jeroen@nospam.please> - 2016-11-04 17:16 +0100
    Re: 5V 200mA LDO with 0.5% accuracy bloggs.fredbloggs.fred@gmail.com - 2016-11-04 11:02 -0700
      Re: 5V 200mA LDO with 0.5% accuracy Winfield Hill <hill@rowland.harvard.edu> - 2016-11-04 12:21 -0700

#433783 — 5V 200mA LDO with 0.5% accuracy

 Low-voltage devices need not apply, need 14V min.
 Power package.  Would like 0.5% accuracy, but will 
 take 1%.  Only ON Semi's version of NSC's ancient
 LP2950A, in DPak, seems to qualify.  Can this be?


-- 
 Thanks,
    - Win

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#433799

On Friday, November 4, 2016 at 12:52:27 PM UTC+11, Winfield Hill wrote:
> Low-voltage devices need not apply, need 14V min.
>  Power package.  Would like 0.5% accuracy, but will 
>  take 1%.  Only ON Semi's version of NSC's ancient
>  LP2950A, in DPak, seems to qualify.  Can this be?

Why would they put a precision voltage reference in the same package as an LDO?

The application  notes are full of examples where an LDO is used as the protected output device on a precision regulator.

Semiconductor manufacturers make integrated circuits that they can sell in huge volumes. Collaborators with physicists have the task of using them to do the jobs that a very few physicists want done.

-- 
Bill Sloman, Sydney

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#433800

On 3 Nov 2016 18:52:13 -0700, the renowned Winfield Hill
<hill@rowland.harvard.edu> wrote:

> Low-voltage devices need not apply, need 14V min.
> Power package.  Would like 0.5% accuracy, but will 
> take 1%.  Only ON Semi's version of NSC's ancient
> LP2950A, in DPak, seems to qualify.  Can this be?

The Venn diagram gets a little slivery when you combine power + tight
tolerance + high voltage but here are a couple that are pretty good,
and a few more that are close. I didn't do an exhaustive search. 


LDFM50PT-TR  16V 1% 500mA 0.125V dropout at 0.5A  $1.36 <---- 

ADP7118 (exposed pad, probably marginal or too low power) 

BD3571 series- 2% but over -40~+125°C, 50V in, power. 

MIC5201 SOT-223 (power?) 1% (2% over temp), 200mA  <----

LT1129 +/- 1.5% 

LP2954 +/- 1.2% 


--sp 


-- 
Best regards, 
Spehro Pefhany
Amazon link for AoE 3rd Edition:            http://tinyurl.com/ntrpwu8

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#433839

Spehro Pefhany wrote...
>
> On 3 Nov 2016 18:52:13, Winfield Hill wrote:
>
>> Low-voltage devices need not apply, need 14V min.
>> Power package.  Would like 0.5% accuracy, but will 
>> take 1%.  Only ON Semi's version of NSC's ancient
>> LP2950A, in DPak, seems to qualify.  Can this be?
>
> The Venn diagram gets a little slivery when you combine
> power + tight tolerance + high voltage but here are a
> couple that are pretty good, and a few more that are
> close. I didn't do an exhaustive search. 

 Hey, Spef, for a non-exhaustive search, you found a
 lot!  More than I found in AoE-III Tables 9.3 amd 9.8,
 plus another 30 minutes of poking around!  Thanks!! 

 You also included SOT-223 stuff, which I was going
 to add to my list of qualifications, since it's a
 nice small power package.

>LDFM50PT-TR  16V 1% 500mA 0.125V dropout at 0.5A  $1.36 <--
>ADP7118 (exposed pad, probably marginal or too low power) 
>BD3571 series- 2% but over -40~+125°C, 50V in, power. 
>MIC5201 SOT-223 (power?) 1% (2% over temp), 200mA  <--
>LT1129 +/- 1.5% 
>LP2954 +/- 1.2% 

 I liked ST's LDFM50, good for 500mA in DPak-5.
 The MIC5201 is nice, but spec'd for 200mA, I then
 noticed their MIC5209, 1%, 500mA and SOT-223 <---
 The LT1129, nice SOT-223-5, is rated 1.5%.  I also
 found the TPS73601, 400mA in a SOT-223-6 package,
 rated at 0.5%, very nice, but adjustable for 5V,
 have to add 1% resistors and degrade the accuracy.
 (TPS73650DCQ avail only at Rochester Electronics.)

 Bill speculates about what usefulness for a 5V 1%
 regulator, but there's a good use I have in mind.

 I'm designing a high-efficiency DC boost testbed.
 In our case, for matching small solar cells to an
 electrochemical cell.  But this testbed, to try
 various inductors, etc, working to reach say 98%
 efficiency, needs an accurate measuring ability.

 In our case, adding MPPT, good for anything solar,
 means adding a PWM stage after the boost converter,
 to match the electrochemical cell's load to the
 sun's output at any point.  So it seems natural to
 shape my PCB into an Arduino shield, and let that
 take measurements and run the MPPT show.  So, how
 to setup a precision 5.00V reference, and also run
 the Arduino, along with whatever else might get
 added on.  Using an LDO means one could power the
 board from an external USB, etc., or a 9V battery.

 Anyway, thanks very much for the help, it gets me
 past a little impasse.


-- 
 Thanks,
    - Win

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#433904

On Friday, 4 November 2016 09:34:44 UTC-4, Winfield Hill  wrote:

>  Anyway, thanks very much for the help, it gets me
>  past a little impasse.
> 
> 
> -- 
>  Thanks,
>     - Win

No problem. In the past I've sometimes used two regulators or a regulator and a 5V series reference. They are powered from the same input. 

There is no heating in the reference/reference regulator so the accuracy is improved and the other one does the heavy lifting current-wise. Since they're powered from the same source, sequencing issues are mostly absent. 

--sp 

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#433835

On 04/11/2016 01:52, Winfield Hill wrote:
>  Low-voltage devices need not apply, need 14V min.
>  Power package.  Would like 0.5% accuracy, but will
>  take 1%.  Only ON Semi's version of NSC's ancient
>  LP2950A, in DPak, seems to qualify.  Can this be?
>
>
Microchip MCP1702 flavour is my favourite. 13.6 Vin though... <2uA 
quiescent !
I use them everwhere I can...

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

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#433841

TTman wrote...
>
>On 04/11/2016 01:52, Winfield Hill wrote:
>>  Low-voltage devices need not apply, need 14V min.
>>  Power package.  Would like 0.5% accuracy, but will
>>  take 1%.  Only ON Semi's version of NSC's ancient
>>  LP2950A, in DPak, seems to qualify.  Can this be?
>
> Microchip MCP1702 flavour is my favourite. 13.6 Vin
> though... <2uA quiescent! I use them everwhere I can...

 That one is indeed vary nice.  But with a 2% spec.


-- 
 Thanks,
    - Win

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#433898

On 04/11/2016 13:43, Winfield Hill wrote:
> TTman wrote...
>>
>> On 04/11/2016 01:52, Winfield Hill wrote:
>>>  Low-voltage devices need not apply, need 14V min.
>>>  Power package.  Would like 0.5% accuracy, but will
>>>  take 1%.  Only ON Semi's version of NSC's ancient
>>>  LP2950A, in DPak, seems to qualify.  Can this be?
>>
>> Microchip MCP1702 flavour is my favourite. 13.6 Vin
>> though... <2uA quiescent! I use them everwhere I can...
>
>  That one is indeed vary nice.  But with a 2% spec.
>
>
I thought the data sheet said 0.4% ? Not that it's an issue for me...

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#434136

On 11/04/2016 09:24 AM, TTman wrote:
> On 04/11/2016 01:52, Winfield Hill wrote:
>>  Low-voltage devices need not apply, need 14V min.
>>  Power package.  Would like 0.5% accuracy, but will
>>  take 1%.  Only ON Semi's version of NSC's ancient
>>  LP2950A, in DPak, seems to qualify.  Can this be?
>>
>>
> Microchip MCP1702 flavour is my favourite. 13.6 Vin though... <2uA
> quiescent !
> I use them everwhere I can...
> 
> ---
> This email has been checked for viruses by Avast antivirus software.
> https://www.avast.com/antivirus
> 
 8 uV 1-Hz noise, though, yuck!

Cheers

Phil Hobbs

-- 
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net

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#433836

On 3 Nov 2016 18:52:13 -0700, Winfield Hill <hill@rowland.harvard.edu> wrote:

> Low-voltage devices need not apply, need 14V min.
> Power package.  Would like 0.5% accuracy, but will 
> take 1%.  Only ON Semi's version of NSC's ancient
> LP2950A, in DPak, seems to qualify.  Can this be?

Seiko S-1142D50I-E6T1U  


Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs (among other things) http://www.viatrack.ca

void _-void-_ in the obvious place

 

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This email has been checked for viruses by Avast antivirus software.
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#433844

Boris Mohar wrote...
>
>On 3 Nov 2016 18:52:13 -0700, Winfield Hill <hill@rowland.harvard.edu> wrote:
>
>> Low-voltage devices need not apply, need 14V min.
>> Power package.  Would like 0.5% accuracy, but will 
>> take 1%.  Only ON Semi's version of NSC's ancient
>> LP2950A, in DPak, seems to qualify.  Can this be?
>
> Seiko S-1142D50I-E6T1U  

 Thanks, Boris!
 S-1142, HSOP-6 package, 5x6mm, very interesting!


-- 
 Thanks,
    - Win

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#433842

On 04/11/16 02:52, Winfield Hill wrote:
>  Low-voltage devices need not apply, need 14V min.
>  Power package.  Would like 0.5% accuracy, but will 
>  take 1%.  Only ON Semi's version of NSC's ancient
>  LP2950A, in DPak, seems to qualify.  Can this be?
> 
> 

<http://www.electronics-eetimes.com/news/precision-voltage-reference-drives-200ma>

<http://www.linear.com/product/LT6658>

Linear Technology LT6658 can get 200 mA at 0.05% accuracy, with up to
36V input.

I haven't used it myself, I just happened to see the advert a couple of
minutes ago.

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#433888

On Friday, November 4, 2016 at 6:44:30 AM UTC-7, David Brown wrote:
> On 04/11/16 02:52, Winfield Hill wrote:
> >  Low-voltage devices need not apply, need 14V min.
> >  Power package.  Would like 0.5% accuracy, but will 
> >  take 1%. 

> <http://www.linear.com/product/LT6658>
> 
> Linear Technology LT6658 can get 200 mA at 0.05% accuracy, with up to
> 36V input.

Interesting part; it has a precision reference, and two four-terminal
regulators (separate pins for IN, OUTforce,OUTsense, GND), so even
though the output is limited to 2.5 to 6V, you can build a ~33V LDO
by using a PNP pass transistor and driving the base from the IN pin.   Just
resistor-load the OUTforce pin rather than connecting it to the real output.

Can't see the datasheet, though: some kind of error  in my browser.

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#433859

On 3 Nov 2016 18:52:13 -0700, Winfield Hill <hill@rowland.harvard.edu>
wrote:

> Low-voltage devices need not apply, need 14V min.
> Power package.  Would like 0.5% accuracy, but will 
> take 1%.  Only ON Semi's version of NSC's ancient
> LP2950A, in DPak, seems to qualify.  Can this be?

Do you have a voltage reference handy? An opamp, an LM317/1117 type,
and a few discretes will make a good precision regulator. 

Sort of like this.

https://dl.dropboxusercontent.com/u/53724080/Circuits/Power/Fan_Regulator.jpg

Regulator self-heating doesn't affect voltage accuracy... which the
fan doesn't need. The 317 isn't inside the feedback loop here, but
could be.

A depletion fet would be interesting, too.

We are discouraged from adding a lot of new parts to the stockroom, so
we often make circuits like this.



-- 

John Larkin         Highland Technology, Inc

lunatic fringe electronics 

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#433860

On Friday, November 4, 2016 at 11:23:54 AM UTC-4, John Larkin wrote:
> On 3 Nov 2016 18:52:13 -0700, Winfield Hill <hill@rowland.harvard.edu>
> wrote:
> 
> > Low-voltage devices need not apply, need 14V min.
> > Power package.  Would like 0.5% accuracy, but will 
> > take 1%.  Only ON Semi's version of NSC's ancient
> > LP2950A, in DPak, seems to qualify.  Can this be?
> 
> Do you have a voltage reference handy? An opamp, an LM317/1117 type,
> and a few discretes will make a good precision regulator. 
> 
> Sort of like this.
> 
> https://dl.dropboxusercontent.com/u/53724080/Circuits/Power/Fan_Regulator.jpg

Huh... Can you get any sort of speed out of that if you wiggle the input 
around?  (say a few kHz.)

George H. 
> 
> Regulator self-heating doesn't affect voltage accuracy... which the
> fan doesn't need. The 317 isn't inside the feedback loop here, but
> could be.
> 
> A depletion fet would be interesting, too.
> 
> We are discouraged from adding a lot of new parts to the stockroom, so
> we often make circuits like this.
> 
> 
> 
> -- 
> 
> John Larkin         Highland Technology, Inc
> 
> lunatic fringe electronics

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#433861

On Fri, 4 Nov 2016 08:33:45 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

>On Friday, November 4, 2016 at 11:23:54 AM UTC-4, John Larkin wrote:
>> On 3 Nov 2016 18:52:13 -0700, Winfield Hill <hill@rowland.harvard.edu>
>> wrote:
>> 
>> > Low-voltage devices need not apply, need 14V min.
>> > Power package.  Would like 0.5% accuracy, but will 
>> > take 1%.  Only ON Semi's version of NSC's ancient
>> > LP2950A, in DPak, seems to qualify.  Can this be?
>> 
>> Do you have a voltage reference handy? An opamp, an LM317/1117 type,
>> and a few discretes will make a good precision regulator. 
>> 
>> Sort of like this.
>> 
>> https://dl.dropboxusercontent.com/u/53724080/Circuits/Power/Fan_Regulator.jpg
>
>Huh... Can you get any sort of speed out of that if you wiggle the input 
>around?  (say a few kHz.)

The big output cap slows things down. The fan doesn't care. We'll
sense PCB temp and probably do a simple slew-limited bang-bang control
loop, basically an up-down counter.

Reminds me, I've got to check that a 317 is stable with that polymer
cap. I'll breadboard that, but I do think I have an LM317 Spice model
around somewhere... of unknown accuracy.




-- 

John Larkin         Highland Technology, Inc

lunatic fringe electronics 

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#433862

On 2016-11-04 16:50, John Larkin wrote:
> On Fri, 4 Nov 2016 08:33:45 -0700 (PDT), George Herold
> <gherold@teachspin.com> wrote:
>
>> On Friday, November 4, 2016 at 11:23:54 AM UTC-4, John Larkin wrote:
>>> On 3 Nov 2016 18:52:13 -0700, Winfield Hill <hill@rowland.harvard.edu>
>>> wrote:
>>>
>>>> Low-voltage devices need not apply, need 14V min.
>>>> Power package.  Would like 0.5% accuracy, but will
>>>> take 1%.  Only ON Semi's version of NSC's ancient
>>>> LP2950A, in DPak, seems to qualify.  Can this be?
>>>
>>> Do you have a voltage reference handy? An opamp, an LM317/1117 type,
>>> and a few discretes will make a good precision regulator.
>>>
>>> Sort of like this.
>>>
>>> https://dl.dropboxusercontent.com/u/53724080/Circuits/Power/Fan_Regulator.jpg
>>
>> Huh... Can you get any sort of speed out of that if you wiggle the input
>> around?  (say a few kHz.)
>
> The big output cap slows things down. The fan doesn't care. We'll
> sense PCB temp and probably do a simple slew-limited bang-bang control
> loop, basically an up-down counter.
>
> Reminds me, I've got to check that a 317 is stable with that polymer
> cap. I'll breadboard that, but I do think I have an LM317 Spice model
> around somewhere... of unknown accuracy.

LM317 should be OK. LM337 is not.

Jeroen Belleman

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#433879

On Thursday, November 3, 2016 at 9:52:27 PM UTC-4, Winfield Hill wrote:
> Low-voltage devices need not apply, need 14V min.
>  Power package.  Would like 0.5% accuracy, but will 
>  take 1%.  Only ON Semi's version of NSC's ancient
>  LP2950A, in DPak, seems to qualify.  Can this be?
> 
> 
> -- 
>  Thanks,
>     - Win

Ordinarily the old pre-regulator trick using two regulators would work but you threw a wrench into the works with that USB source stuff. Doesn't the USB ideally supply 5.000V, so how you expect to keep a 5V regulator within 0.5% (25mV ?!?) at 200mA loading?

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#433894

bloggs.fredbloggs.fred@gmail.com wrote...
>
> Winfield Hill wrote:
>> Low-voltage devices need not apply, need 14V min.
>> Power package.  Would like 0.5% accuracy, but will
>> take 1%.  Only ON Semi's version of NSC's ancient
>> LP2950A, in DPak, seems to qualify.  Can this be?
>
> Ordinarily the old pre-regulator trick using two
> regulators would work but you threw a wrench into
> the works with that USB source stuff. 

 My testbed board can be used in a variety of
 ways and with a variety of power sources. 
 Of course in the event of a USB source, an
 accurate 5V goes out the window.  But that's
 not too bad; I'm using a 4.096V reference IC
 for the onboard ADC.


-- 
 Thanks,
    - Win

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