> On Sat, 25 Jun 2011 07:54:24 -0700, Joerg <invalid@invalid.invalid>
> wrote:
>
>> John Larkin wrote:
>>> On Wed, 22 Jun 2011 06:32:16 -0400, JW <none@dev.null> wrote:
>>>
>>>> On Tue, 21 Jun 2011 10:48:26 -0700 John Larkin
>>>> <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in Message id:
>>>> <ful107hc4if8pdn1eukhnbavctl33j7o4j@4ax.com>:
>>>>
>>>>> I'm making some replacement boards for a system I designed a while
>>>>> ago. 1980, actually. The power regulator board used a couple of
>>>>> LM376's, a nice little DIP8 voltage regulator that drives an off-board
>>>>> heatsunk PNP pass transistor.
>>>>>
>>>>> LM376 seems to be unavailable. But I can't find a substitute, namely a
>>>>> linear voltage regulator controller with foldback capability and
>>>>> external PNP pass transistor. Well, you could hack it with a 723, an
>>>>> even more ancient part.
>>>>>
>>>>> Strange that there's no equivalent, at least none I can find. Anybody
>>>>> know of one? I could make it out of opamps and stuff, I guess, or use
>>>>> an LM1117 in PNP-boost mode, with extra junk for the current liniting.
>>>>>
>>>>> The 376 was so elegant.
>>>> According to http://www.national.com/kbase/category/Power.html#114
>>>> "LM376 was an LM305 in a plastic DIP package"
>>>>
>>>> Which can still be found, but not cheap by any means.
>>>> http://www.findchips.com/avail?part=LM305
>>>> http://www.oemstrade.com/search/LM305/
>>> I don't think any of them are still in production, and old parts from
>>> brokers are risky.
>>>
>>> Looks like a ua723 will do what I want, but it has a lot of
>>> constraints. I was just sort of surprised that nothing like the 376 is
>>> still made. What do people do when they need a big honking linear
>>> power supply? ...
>>
>> They use a 723 and some big honking transistors on a massive heat sink.
>> Take a look at linear bricks (PowerOne and such), those are a reason the
>> 723 is still around and will be for a long time.
>>
>>
>>> ... Make the controller from a reference and a couple of
>>> opamps and a transistor or two, I guess... a lot of parts to replace
>>> one DIP8. Seems strange that the best, basically only, linear
>>> regulator controller left, the 723, is about 40 years old.
>>>
>> 40 years is no problem for a successful part, and the 723 clearly
>> qualifies as successful. Right up there with the LM317 or Bob Pease's
>> LM337. I remember when a Fairchild sales guy in the 90's wanted to
>> convince me that it would be futile if I designed a circuit with CD4000
>> logic because it'll go obsolete. His new logic parts were more expensive
>> and would have needed a regulator, so naturally I didn't listen.
>> Actually I had a mild ROFL episode about it later. Long story short that
>> unit still rolls off the production floor in quantities in Shenzhen today.
>>
>> There's app notes about the LM723. If you can't find anything I can go
>> through my stash (there's a reason I don't throw out the old printed app
>> notes and databooks). But it'll have to be later because today is the
>> day where SWMBO wants us to move a massive fountain to another spot.
>> Which of course is higher up and can only be reached via rocks. Anyone
>> have a Motrin?
>
> The 723 is horribly under-specified. All the datasheets seem to be
> identical copies of the (Fairchild?) original. If you want to know the
> error amp bias current, you have to look at the schematic and estimate
> it, or measure it. It's not specified.
>
> Apparently the design was pre-bandgap, so it's full of zeners. So it
> won't work below 9.5 volts input. The reference out voltage exceeds
> the max allowed input differential voltage, so you need a voltage
> divider there. The current limit sense needs a full junction drop
> across the sense resistor.
>
> National specs its ESD tolerance as 1200 volts!
>
> It was brilliant 40 years ago. I'm just surprised that it's still
> about as good as you can buy.
>
Well, there ain't no market to write home about. They are mostly used
when people need really low noise or in the linear bricks where the
vendors would like to not have to put any additional R&D whatsoever into
them.
If you want something more modern you'll have to go for a LT1575 or
similar chips:
http://cds.linear.com/docs/Datasheet/15757f.pdf
But they cost almost an order of magnitude more and aren't as versatile.
--
Regards, Joerg
http://www.analogconsultants.com/
"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
Reply by John Larkin●June 25, 20112011-06-25
On Sat, 25 Jun 2011 07:54:24 -0700, Joerg <invalid@invalid.invalid>
wrote:
>John Larkin wrote:
>> On Wed, 22 Jun 2011 06:32:16 -0400, JW <none@dev.null> wrote:
>>
>>> On Tue, 21 Jun 2011 10:48:26 -0700 John Larkin
>>> <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in Message id:
>>> <ful107hc4if8pdn1eukhnbavctl33j7o4j@4ax.com>:
>>>
>>>>
>>>> I'm making some replacement boards for a system I designed a while
>>>> ago. 1980, actually. The power regulator board used a couple of
>>>> LM376's, a nice little DIP8 voltage regulator that drives an off-board
>>>> heatsunk PNP pass transistor.
>>>>
>>>> LM376 seems to be unavailable. But I can't find a substitute, namely a
>>>> linear voltage regulator controller with foldback capability and
>>>> external PNP pass transistor. Well, you could hack it with a 723, an
>>>> even more ancient part.
>>>>
>>>> Strange that there's no equivalent, at least none I can find. Anybody
>>>> know of one? I could make it out of opamps and stuff, I guess, or use
>>>> an LM1117 in PNP-boost mode, with extra junk for the current liniting.
>>>>
>>>> The 376 was so elegant.
>>> According to http://www.national.com/kbase/category/Power.html#114
>>> "LM376 was an LM305 in a plastic DIP package"
>>>
>>> Which can still be found, but not cheap by any means.
>>> http://www.findchips.com/avail?part=LM305
>>> http://www.oemstrade.com/search/LM305/
>>
>> I don't think any of them are still in production, and old parts from
>> brokers are risky.
>>
>> Looks like a ua723 will do what I want, but it has a lot of
>> constraints. I was just sort of surprised that nothing like the 376 is
>> still made. What do people do when they need a big honking linear
>> power supply? ...
>
>
>They use a 723 and some big honking transistors on a massive heat sink.
>Take a look at linear bricks (PowerOne and such), those are a reason the
>723 is still around and will be for a long time.
>
>
>> ... Make the controller from a reference and a couple of
>> opamps and a transistor or two, I guess... a lot of parts to replace
>> one DIP8. Seems strange that the best, basically only, linear
>> regulator controller left, the 723, is about 40 years old.
>>
>
>40 years is no problem for a successful part, and the 723 clearly
>qualifies as successful. Right up there with the LM317 or Bob Pease's
>LM337. I remember when a Fairchild sales guy in the 90's wanted to
>convince me that it would be futile if I designed a circuit with CD4000
>logic because it'll go obsolete. His new logic parts were more expensive
>and would have needed a regulator, so naturally I didn't listen.
>Actually I had a mild ROFL episode about it later. Long story short that
>unit still rolls off the production floor in quantities in Shenzhen today.
>
>There's app notes about the LM723. If you can't find anything I can go
>through my stash (there's a reason I don't throw out the old printed app
>notes and databooks). But it'll have to be later because today is the
>day where SWMBO wants us to move a massive fountain to another spot.
>Which of course is higher up and can only be reached via rocks. Anyone
>have a Motrin?
The 723 is horribly under-specified. All the datasheets seem to be
identical copies of the (Fairchild?) original. If you want to know the
error amp bias current, you have to look at the schematic and estimate
it, or measure it. It's not specified.
Apparently the design was pre-bandgap, so it's full of zeners. So it
won't work below 9.5 volts input. The reference out voltage exceeds
the max allowed input differential voltage, so you need a voltage
divider there. The current limit sense needs a full junction drop
across the sense resistor.
National specs its ESD tolerance as 1200 volts!
It was brilliant 40 years ago. I'm just surprised that it's still
about as good as you can buy.
John
Reply by Jim Thompson●June 25, 20112011-06-25
On Sat, 25 Jun 2011 08:03:02 -0700, Joerg <invalid@invalid.invalid>
wrote:
>Jim Thompson wrote:
>> On Sat, 25 Jun 2011 07:54:24 -0700, Joerg <invalid@invalid.invalid>
>> wrote:
>>
>>> John Larkin wrote:
>>>> On Wed, 22 Jun 2011 06:32:16 -0400, JW <none@dev.null> wrote:
>>>>
>>>>> On Tue, 21 Jun 2011 10:48:26 -0700 John Larkin
>>>>> <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in Message id:
>>>>> <ful107hc4if8pdn1eukhnbavctl33j7o4j@4ax.com>:
>>>>>
>>>>>> I'm making some replacement boards for a system I designed a while
>>>>>> ago. 1980, actually. The power regulator board used a couple of
>>>>>> LM376's, a nice little DIP8 voltage regulator that drives an off-board
>>>>>> heatsunk PNP pass transistor.
>>>>>>
>>>>>> LM376 seems to be unavailable. But I can't find a substitute, namely a
>>>>>> linear voltage regulator controller with foldback capability and
>>>>>> external PNP pass transistor. Well, you could hack it with a 723, an
>>>>>> even more ancient part.
>>>>>>
>>>>>> Strange that there's no equivalent, at least none I can find. Anybody
>>>>>> know of one? I could make it out of opamps and stuff, I guess, or use
>>>>>> an LM1117 in PNP-boost mode, with extra junk for the current liniting.
>>>>>>
>>>>>> The 376 was so elegant.
>>>>> According to http://www.national.com/kbase/category/Power.html#114
>>>>> "LM376 was an LM305 in a plastic DIP package"
>>>>>
>>>>> Which can still be found, but not cheap by any means.
>>>>> http://www.findchips.com/avail?part=LM305
>>>>> http://www.oemstrade.com/search/LM305/
>>>> I don't think any of them are still in production, and old parts from
>>>> brokers are risky.
>>>>
>>>> Looks like a ua723 will do what I want, but it has a lot of
>>>> constraints. I was just sort of surprised that nothing like the 376 is
>>>> still made. What do people do when they need a big honking linear
>>>> power supply? ...
>>>
>>> They use a 723 and some big honking transistors on a massive heat sink.
>>> Take a look at linear bricks (PowerOne and such), those are a reason the
>>> 723 is still around and will be for a long time.
>>>
>>>
>>>> ... Make the controller from a reference and a couple of
>>>> opamps and a transistor or two, I guess... a lot of parts to replace
>>>> one DIP8. Seems strange that the best, basically only, linear
>>>> regulator controller left, the 723, is about 40 years old.
>>>>
>>> 40 years is no problem for a successful part, and the 723 clearly
>>> qualifies as successful. Right up there with the LM317 or Bob Pease's
>>> LM337. I remember when a Fairchild sales guy in the 90's wanted to
>>> convince me that it would be futile if I designed a circuit with CD4000
>>> logic because it'll go obsolete. His new logic parts were more expensive
>>> and would have needed a regulator, so naturally I didn't listen.
>>> Actually I had a mild ROFL episode about it later. Long story short that
>>> unit still rolls off the production floor in quantities in Shenzhen today.
>>>
>>> There's app notes about the LM723. If you can't find anything I can go
>>> through my stash (there's a reason I don't throw out the old printed app
>>> notes and databooks). But it'll have to be later because today is the
>>> day where SWMBO wants us to move a massive fountain to another spot.
>>> Which of course is higher up and can only be reached via rocks. Anyone
>>> have a Motrin?
>>
>> Why not an OpAmp, a reference (say a TL431), plus your power device...
>> can't anyone think feedback anymore?
>>
>
>Sure, but you have to add lots of stuff. Typically, you'd also want
>over-current limitation and such things. The 723 has all that nicely
>tucked into a single package.
>
>If you can get all this in a 25c industry standard chip why would anyone
>want to build it with more parts and at higher cost than necessary?
Sometimes one designs for quality and reliability.
But sometimes even _I_ squeeze to save space... just recently,
pondering how to do a _full-swing_ wired-OR from a pair of inverters
(NOT open drain), I remembered the input stage of TTL... 2 NPN's plus
one resistor :-)
...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Reply by Joerg●June 25, 20112011-06-25
Jim Thompson wrote:
> On Sat, 25 Jun 2011 07:54:24 -0700, Joerg <invalid@invalid.invalid>
> wrote:
>
>> John Larkin wrote:
>>> On Wed, 22 Jun 2011 06:32:16 -0400, JW <none@dev.null> wrote:
>>>
>>>> On Tue, 21 Jun 2011 10:48:26 -0700 John Larkin
>>>> <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in Message id:
>>>> <ful107hc4if8pdn1eukhnbavctl33j7o4j@4ax.com>:
>>>>
>>>>> I'm making some replacement boards for a system I designed a while
>>>>> ago. 1980, actually. The power regulator board used a couple of
>>>>> LM376's, a nice little DIP8 voltage regulator that drives an off-board
>>>>> heatsunk PNP pass transistor.
>>>>>
>>>>> LM376 seems to be unavailable. But I can't find a substitute, namely a
>>>>> linear voltage regulator controller with foldback capability and
>>>>> external PNP pass transistor. Well, you could hack it with a 723, an
>>>>> even more ancient part.
>>>>>
>>>>> Strange that there's no equivalent, at least none I can find. Anybody
>>>>> know of one? I could make it out of opamps and stuff, I guess, or use
>>>>> an LM1117 in PNP-boost mode, with extra junk for the current liniting.
>>>>>
>>>>> The 376 was so elegant.
>>>> According to http://www.national.com/kbase/category/Power.html#114
>>>> "LM376 was an LM305 in a plastic DIP package"
>>>>
>>>> Which can still be found, but not cheap by any means.
>>>> http://www.findchips.com/avail?part=LM305
>>>> http://www.oemstrade.com/search/LM305/
>>> I don't think any of them are still in production, and old parts from
>>> brokers are risky.
>>>
>>> Looks like a ua723 will do what I want, but it has a lot of
>>> constraints. I was just sort of surprised that nothing like the 376 is
>>> still made. What do people do when they need a big honking linear
>>> power supply? ...
>>
>> They use a 723 and some big honking transistors on a massive heat sink.
>> Take a look at linear bricks (PowerOne and such), those are a reason the
>> 723 is still around and will be for a long time.
>>
>>
>>> ... Make the controller from a reference and a couple of
>>> opamps and a transistor or two, I guess... a lot of parts to replace
>>> one DIP8. Seems strange that the best, basically only, linear
>>> regulator controller left, the 723, is about 40 years old.
>>>
>> 40 years is no problem for a successful part, and the 723 clearly
>> qualifies as successful. Right up there with the LM317 or Bob Pease's
>> LM337. I remember when a Fairchild sales guy in the 90's wanted to
>> convince me that it would be futile if I designed a circuit with CD4000
>> logic because it'll go obsolete. His new logic parts were more expensive
>> and would have needed a regulator, so naturally I didn't listen.
>> Actually I had a mild ROFL episode about it later. Long story short that
>> unit still rolls off the production floor in quantities in Shenzhen today.
>>
>> There's app notes about the LM723. If you can't find anything I can go
>> through my stash (there's a reason I don't throw out the old printed app
>> notes and databooks). But it'll have to be later because today is the
>> day where SWMBO wants us to move a massive fountain to another spot.
>> Which of course is higher up and can only be reached via rocks. Anyone
>> have a Motrin?
>
> Why not an OpAmp, a reference (say a TL431), plus your power device...
> can't anyone think feedback anymore?
>
Sure, but you have to add lots of stuff. Typically, you'd also want
over-current limitation and such things. The 723 has all that nicely
tucked into a single package.
If you can get all this in a 25c industry standard chip why would anyone
want to build it with more parts and at higher cost than necessary?
--
Regards, Joerg
http://www.analogconsultants.com/
"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
Reply by Jim Thompson●June 25, 20112011-06-25
On Sat, 25 Jun 2011 07:54:24 -0700, Joerg <invalid@invalid.invalid>
wrote:
>John Larkin wrote:
>> On Wed, 22 Jun 2011 06:32:16 -0400, JW <none@dev.null> wrote:
>>
>>> On Tue, 21 Jun 2011 10:48:26 -0700 John Larkin
>>> <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in Message id:
>>> <ful107hc4if8pdn1eukhnbavctl33j7o4j@4ax.com>:
>>>
>>>>
>>>> I'm making some replacement boards for a system I designed a while
>>>> ago. 1980, actually. The power regulator board used a couple of
>>>> LM376's, a nice little DIP8 voltage regulator that drives an off-board
>>>> heatsunk PNP pass transistor.
>>>>
>>>> LM376 seems to be unavailable. But I can't find a substitute, namely a
>>>> linear voltage regulator controller with foldback capability and
>>>> external PNP pass transistor. Well, you could hack it with a 723, an
>>>> even more ancient part.
>>>>
>>>> Strange that there's no equivalent, at least none I can find. Anybody
>>>> know of one? I could make it out of opamps and stuff, I guess, or use
>>>> an LM1117 in PNP-boost mode, with extra junk for the current liniting.
>>>>
>>>> The 376 was so elegant.
>>> According to http://www.national.com/kbase/category/Power.html#114
>>> "LM376 was an LM305 in a plastic DIP package"
>>>
>>> Which can still be found, but not cheap by any means.
>>> http://www.findchips.com/avail?part=LM305
>>> http://www.oemstrade.com/search/LM305/
>>
>> I don't think any of them are still in production, and old parts from
>> brokers are risky.
>>
>> Looks like a ua723 will do what I want, but it has a lot of
>> constraints. I was just sort of surprised that nothing like the 376 is
>> still made. What do people do when they need a big honking linear
>> power supply? ...
>
>
>They use a 723 and some big honking transistors on a massive heat sink.
>Take a look at linear bricks (PowerOne and such), those are a reason the
>723 is still around and will be for a long time.
>
>
>> ... Make the controller from a reference and a couple of
>> opamps and a transistor or two, I guess... a lot of parts to replace
>> one DIP8. Seems strange that the best, basically only, linear
>> regulator controller left, the 723, is about 40 years old.
>>
>
>40 years is no problem for a successful part, and the 723 clearly
>qualifies as successful. Right up there with the LM317 or Bob Pease's
>LM337. I remember when a Fairchild sales guy in the 90's wanted to
>convince me that it would be futile if I designed a circuit with CD4000
>logic because it'll go obsolete. His new logic parts were more expensive
>and would have needed a regulator, so naturally I didn't listen.
>Actually I had a mild ROFL episode about it later. Long story short that
>unit still rolls off the production floor in quantities in Shenzhen today.
>
>There's app notes about the LM723. If you can't find anything I can go
>through my stash (there's a reason I don't throw out the old printed app
>notes and databooks). But it'll have to be later because today is the
>day where SWMBO wants us to move a massive fountain to another spot.
>Which of course is higher up and can only be reached via rocks. Anyone
>have a Motrin?
Why not an OpAmp, a reference (say a TL431), plus your power device...
can't anyone think feedback anymore?
...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
Reply by Joerg●June 25, 20112011-06-25
Martin Riddle wrote:
> "John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in
> message news:6h5407dsb6ncpnpi87rong51hf6s2bnb33@4ax.com...
>> On Wed, 22 Jun 2011 16:57:27 +0100, <news@rblack01.plus.com> wrote:
>>
>>> In article <ful107hc4if8pdn1eukhnbavctl33j7o4j@4ax.com>,
>>> jjlarkin@highNOTlandTHIStechnologyPART.com says...
>>>>
>>>> I'm making some replacement boards for a system I designed a while
>>>> ago. 1980, actually. The power regulator board used a couple of
>>>> LM376's, a nice little DIP8 voltage regulator that drives an
>>>> off-board
>>>> heatsunk PNP pass transistor.
>>>>
>>>> LM376 seems to be unavailable. But I can't find a substitute, namely
>>>> a
>>>> linear voltage regulator controller with foldback capability and
>>>> external PNP pass transistor. Well, you could hack it with a 723, an
>>>> even more ancient part.
>>>>
>>>> Strange that there's no equivalent, at least none I can find.
>>>> Anybody
>>>> know of one? I could make it out of opamps and stuff, I guess, or
>>>> use
>>>> an LM1117 in PNP-boost mode, with extra junk for the current
>>>> liniting.
>>>>
>>>> The 376 was so elegant.
>>>>
>>>> John
>>>>
>>>>
>>> Is this any good?
>>>
>>> www.micrel.com/page.do?page=/product-info/products/mic5156.shtml
>>>
>>> Uses a N MOSFET as the pass element instead of a PNP so not a drop-in
>>> replacement.
>>>
>>> I used one, ages ago, on a dev board. No stability issues, it just
>>> worked. It seems to still be in production, Digikey has them in
>>> stock.
>>>
>>> HTH
>>>
>>> R.
>> Unfortunately, it won't work with my constraints.
>>
>> But it is a cool part. I was just doodling a new project idea this
>> morning, and it would need a bunch of adjustable regulators with
>> precise current limiting, and this might be just the ticket.
>>
>> John
>>
>
> Linear has more stable linear regulators. The 5156's 2% is'nt that
> great.
> But micrel does have some neat stuff, particularly their high side
> drivers since they can switch right up to the rails.
>
The good thing is LTC usually doesn't obsolete stuff until they have
called pretty much anyone who has ever bought one of those parts, and no
orders have come in during the last few years. Just to make sure. But
prices are often a bit steep.
--
Regards, Joerg
http://www.analogconsultants.com/
"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
Reply by Joerg●June 25, 20112011-06-25
John Larkin wrote:
> On Wed, 22 Jun 2011 06:32:16 -0400, JW <none@dev.null> wrote:
>
>> On Tue, 21 Jun 2011 10:48:26 -0700 John Larkin
>> <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in Message id:
>> <ful107hc4if8pdn1eukhnbavctl33j7o4j@4ax.com>:
>>
>>>
>>> I'm making some replacement boards for a system I designed a while
>>> ago. 1980, actually. The power regulator board used a couple of
>>> LM376's, a nice little DIP8 voltage regulator that drives an off-board
>>> heatsunk PNP pass transistor.
>>>
>>> LM376 seems to be unavailable. But I can't find a substitute, namely a
>>> linear voltage regulator controller with foldback capability and
>>> external PNP pass transistor. Well, you could hack it with a 723, an
>>> even more ancient part.
>>>
>>> Strange that there's no equivalent, at least none I can find. Anybody
>>> know of one? I could make it out of opamps and stuff, I guess, or use
>>> an LM1117 in PNP-boost mode, with extra junk for the current liniting.
>>>
>>> The 376 was so elegant.
>> According to http://www.national.com/kbase/category/Power.html#114
>> "LM376 was an LM305 in a plastic DIP package"
>>
>> Which can still be found, but not cheap by any means.
>> http://www.findchips.com/avail?part=LM305
>> http://www.oemstrade.com/search/LM305/
>
> I don't think any of them are still in production, and old parts from
> brokers are risky.
>
> Looks like a ua723 will do what I want, but it has a lot of
> constraints. I was just sort of surprised that nothing like the 376 is
> still made. What do people do when they need a big honking linear
> power supply? ...
They use a 723 and some big honking transistors on a massive heat sink.
Take a look at linear bricks (PowerOne and such), those are a reason the
723 is still around and will be for a long time.
> ... Make the controller from a reference and a couple of
> opamps and a transistor or two, I guess... a lot of parts to replace
> one DIP8. Seems strange that the best, basically only, linear
> regulator controller left, the 723, is about 40 years old.
>
40 years is no problem for a successful part, and the 723 clearly
qualifies as successful. Right up there with the LM317 or Bob Pease's
LM337. I remember when a Fairchild sales guy in the 90's wanted to
convince me that it would be futile if I designed a circuit with CD4000
logic because it'll go obsolete. His new logic parts were more expensive
and would have needed a regulator, so naturally I didn't listen.
Actually I had a mild ROFL episode about it later. Long story short that
unit still rolls off the production floor in quantities in Shenzhen today.
There's app notes about the LM723. If you can't find anything I can go
through my stash (there's a reason I don't throw out the old printed app
notes and databooks). But it'll have to be later because today is the
day where SWMBO wants us to move a massive fountain to another spot.
Which of course is higher up and can only be reached via rocks. Anyone
have a Motrin?
--
Regards, Joerg
http://www.analogconsultants.com/
"gmail" domain blocked because of excessive spam.
Use another domain or send PM.
Reply by Martin Riddle●June 23, 20112011-06-23
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in
message news:6h5407dsb6ncpnpi87rong51hf6s2bnb33@4ax.com...
> On Wed, 22 Jun 2011 16:57:27 +0100, <news@rblack01.plus.com> wrote:
>
>>In article <ful107hc4if8pdn1eukhnbavctl33j7o4j@4ax.com>,
>>jjlarkin@highNOTlandTHIStechnologyPART.com says...
>>>
>>>
>>> I'm making some replacement boards for a system I designed a while
>>> ago. 1980, actually. The power regulator board used a couple of
>>> LM376's, a nice little DIP8 voltage regulator that drives an
>>> off-board
>>> heatsunk PNP pass transistor.
>>>
>>> LM376 seems to be unavailable. But I can't find a substitute, namely
>>> a
>>> linear voltage regulator controller with foldback capability and
>>> external PNP pass transistor. Well, you could hack it with a 723, an
>>> even more ancient part.
>>>
>>> Strange that there's no equivalent, at least none I can find.
>>> Anybody
>>> know of one? I could make it out of opamps and stuff, I guess, or
>>> use
>>> an LM1117 in PNP-boost mode, with extra junk for the current
>>> liniting.
>>>
>>> The 376 was so elegant.
>>>
>>> John
>>>
>>>
>>
>>Is this any good?
>>
>>www.micrel.com/page.do?page=/product-info/products/mic5156.shtml
>>
>>Uses a N MOSFET as the pass element instead of a PNP so not a drop-in
>>replacement.
>>
>>I used one, ages ago, on a dev board. No stability issues, it just
>>worked. It seems to still be in production, Digikey has them in
>>stock.
>>
>>HTH
>>
>>R.
>
> Unfortunately, it won't work with my constraints.
>
> But it is a cool part. I was just doodling a new project idea this
> morning, and it would need a bunch of adjustable regulators with
> precise current limiting, and this might be just the ticket.
>
> John
>
Linear has more stable linear regulators. The 5156's 2% is'nt that
great.
But micrel does have some neat stuff, particularly their high side
drivers since they can switch right up to the rails.
Cheers
Reply by John Larkin●June 22, 20112011-06-22
On Wed, 22 Jun 2011 16:57:27 +0100, <news@rblack01.plus.com> wrote:
>In article <ful107hc4if8pdn1eukhnbavctl33j7o4j@4ax.com>,
>jjlarkin@highNOTlandTHIStechnologyPART.com says...
>>
>>
>> I'm making some replacement boards for a system I designed a while
>> ago. 1980, actually. The power regulator board used a couple of
>> LM376's, a nice little DIP8 voltage regulator that drives an off-board
>> heatsunk PNP pass transistor.
>>
>> LM376 seems to be unavailable. But I can't find a substitute, namely a
>> linear voltage regulator controller with foldback capability and
>> external PNP pass transistor. Well, you could hack it with a 723, an
>> even more ancient part.
>>
>> Strange that there's no equivalent, at least none I can find. Anybody
>> know of one? I could make it out of opamps and stuff, I guess, or use
>> an LM1117 in PNP-boost mode, with extra junk for the current liniting.
>>
>> The 376 was so elegant.
>>
>> John
>>
>>
>
>Is this any good?
>
>www.micrel.com/page.do?page=/product-info/products/mic5156.shtml
>
>Uses a N MOSFET as the pass element instead of a PNP so not a drop-in
>replacement.
>
>I used one, ages ago, on a dev board. No stability issues, it just
>worked. It seems to still be in production, Digikey has them in stock.
>
>HTH
>
>R.
Unfortunately, it won't work with my constraints.
But it is a cool part. I was just doodling a new project idea this
morning, and it would need a bunch of adjustable regulators with
precise current limiting, and this might be just the ticket.
John
Reply by ●June 22, 20112011-06-22
In article <ful107hc4if8pdn1eukhnbavctl33j7o4j@4ax.com>,
jjlarkin@highNOTlandTHIStechnologyPART.com says...
>
>
> I'm making some replacement boards for a system I designed a while
> ago. 1980, actually. The power regulator board used a couple of
> LM376's, a nice little DIP8 voltage regulator that drives an off-board
> heatsunk PNP pass transistor.
>
> LM376 seems to be unavailable. But I can't find a substitute, namely a
> linear voltage regulator controller with foldback capability and
> external PNP pass transistor. Well, you could hack it with a 723, an
> even more ancient part.
>
> Strange that there's no equivalent, at least none I can find. Anybody
> know of one? I could make it out of opamps and stuff, I guess, or use
> an LM1117 in PNP-boost mode, with extra junk for the current liniting.
>
> The 376 was so elegant.
>
> John
>
>
Is this any good?
www.micrel.com/page.do?page=/product-info/products/mic5156.shtml
Uses a N MOSFET as the pass element instead of a PNP so not a drop-in
replacement.
I used one, ages ago, on a dev board. No stability issues, it just
worked. It seems to still be in production, Digikey has them in stock.
HTH
R.