Favorite Buck Regulators

[Tim Wescott]

24V --> 3.3V, around 250mA, good enough for digital.

There are a bazillion out there -- it seems like anyone who even pretends
to sell analog circuit parts sells these, with a wide variety of price
ranges, features, etc.

So -- who do you think is best, and why? I'm mostly looking for parts
that actually work the way that the data sheet says they will, and that
don't have any really bad "gotchas". If anyone has been particularly bad
about supply hiccups -- mention that, too.

--
www.wescottdesign.com

 

[krw@att.bizzzzzzzzzzzz]

On Thu, 17 Nov 2011 13:18:21 -0600, Tim Wescott <tim@seemywebsite.com> wrote:

24V --> 3.3V, around 250mA, good enough for digital.

There are a bazillion out there -- it seems like anyone who even pretends
to sell analog circuit parts sells these, with a wide variety of price
ranges, features, etc.

So -- who do you think is best, and why? I'm mostly looking for parts
that actually work the way that the data sheet says they will, and that
don't have any really bad "gotchas". If anyone has been particularly bad
about supply hiccups -- mention that, too.

LTC, if you can afford them. Simulation is a big factor. I've had good luck
with TI, too.

 

[Jan Panteltje]

On a sunny day (Thu, 17 Nov 2011 11:47:33 -0800 (PST)) it happened Fred Bloggs
<bloggs.fredbloggs.fred@gmail.com> wrote in
<720a8bdb-a109-4cf7-8270-da172b4f87e4@c18g2000yqj.googlegroups.com>:

NS is #1 in performance in every product line they produce.

I got a bunch of LM2596-33 from ebay, used most of it already.
add an inductor and diode, in-out caps, and it is good to 3 A.
150 kHz, if you add a series resistor in the sense lead you can set it to +5V out or higher too.
L = 33 uH...
I have used it at 200 mA too, input up to 40 V.
I am happy with these.
They are obtainable, high frequency, cheap,
and come in a package that I can see with the naked eye.

 

[Spehro Pefhany]

On Thu, 17 Nov 2011 13:18:21 -0600, Tim Wescott <tim@seemywebsite.com>
wrote:

24V --> 3.3V, around 250mA, good enough for digital.

There are a bazillion out there -- it seems like anyone who even pretends
to sell analog circuit parts sells these, with a wide variety of price
ranges, features, etc.

So -- who do you think is best, and why? I'm mostly looking for parts
that actually work the way that the data sheet says they will, and that
don't have any really bad "gotchas". If anyone has been particularly bad
about supply hiccups -- mention that, too.

Lowest cost will likely be the MC34063. About 20 cents in 1K. Requires
a somewhat bulky ~100uH inductor and a few extra parts- all cheap in
volume. Plenty of sources-- you can hardly go wrong if it meets your
specifications.

Otherwise, try doing a parametric search at TI (who now own National)
and Linear Technology. You can get smaller (higher switching
frequency), lower losses (synchronous MOSFET rather than Schotttky)
etc. etc., but there is a cost in dollars and perhaps availability.

 

[Joerg]

Spehro Pefhany wrote:

On Thu, 17 Nov 2011 13:18:21 -0600, Tim Wescott <tim@seemywebsite.com
wrote:

24V --> 3.3V, around 250mA, good enough for digital.

There are a bazillion out there -- it seems like anyone who even pretends
to sell analog circuit parts sells these, with a wide variety of price
ranges, features, etc.

So -- who do you think is best, and why? I'm mostly looking for parts
that actually work the way that the data sheet says they will, and that
don't have any really bad "gotchas". If anyone has been particularly bad
about supply hiccups -- mention that, too.

Lowest cost will likely be the MC34063. About 20 cents in 1K. Requires
a somewhat bulky ~100uH inductor and a few extra parts- all cheap in
volume. Plenty of sources-- you can hardly go wrong if it meets your
specifications.

I second that. Efficiency isn't stellar but it is sure hard to beat its
advantages, price and 2nd sourcing.

And stay away from vaporware manufacturers.

[...]

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Fred Bloggs]

On Nov 17, 2:18 pm, Tim Wescott <t...@seemywebsite.com> wrote:

24V --> 3.3V, around 250mA, good enough for digital.

There are a bazillion out there -- it seems like anyone who even pretends
to sell analog circuit parts sells these, with a wide variety of price
ranges, features, etc.

So -- who do you think is best, and why?  I'm mostly looking for parts
that actually work the way that the data sheet says they will, and that
don't have any really bad "gotchas".  If anyone has been particularly bad
about supply hiccups -- mention that, too.

--www.wescottdesign.com

NS is #1 in performance in every product line they produce.

 

[Fred Bartoli]

Tim Wescott a ĂŠcrit :

24V --> 3.3V, around 250mA, good enough for digital.

There are a bazillion out there -- it seems like anyone who even pretends
to sell analog circuit parts sells these, with a wide variety of price
ranges, features, etc.

So -- who do you think is best, and why? I'm mostly looking for parts
that actually work the way that the data sheet says they will, and that
don't have any really bad "gotchas". If anyone has been particularly bad
about supply hiccups -- mention that, too.

Recently used several times http://www.linear.com/product/LT3640#overview

Dual channels CM with sync rectifier for the low voltage channel, POR,
watchdog, synchronizable, over 1 amp output current, the QFN28 version
is small enough with a thermal pad...
And at up to 2.5MHz the inductors are small enough...



--
Thanks,
Fred.

 

[Tim Wescott]

On Thu, 17 Nov 2011 13:51:35 -0600, krw@att.bizzzzzzzzzzzz wrote:

On Thu, 17 Nov 2011 13:18:21 -0600, Tim Wescott <tim@seemywebsite.com
wrote:

24V --> 3.3V, around 250mA, good enough for digital.

There are a bazillion out there -- it seems like anyone who even
pretends to sell analog circuit parts sells these, with a wide variety
of price ranges, features, etc.

So -- who do you think is best, and why? I'm mostly looking for parts
that actually work the way that the data sheet says they will, and that
don't have any really bad "gotchas". If anyone has been particularly
bad about supply hiccups -- mention that, too.

LTC, if you can afford them. Simulation is a big factor. I've had good
luck with TI, too.

LT certainly is nice. I had a National apps engineer tell me flat out
that they didn't have behavioral SPICE models of their switching
controllers, and that I should just use their web tool -- which lead me
to tell him flat out that National had just lost a sale (had I been doing
something exactly in line with what the regulator was designed for I may
have had a different answer -- but I still didn't like the attitude of
"oh just use our design tools, you don't actually have to understand what
our products do").

--
www.wescottdesign.com

 

[Nico Coesel]

Tim Wescott <tim@seemywebsite.com> wrote:

24V --> 3.3V, around 250mA, good enough for digital.

There are a bazillion out there -- it seems like anyone who even pretends
to sell analog circuit parts sells these, with a wide variety of price
ranges, features, etc.

So -- who do you think is best, and why? I'm mostly looking for parts
that actually work the way that the data sheet says they will, and that
don't have any really bad "gotchas". If anyone has been particularly bad
about supply hiccups -- mention that, too.

I've used the TPS5410 from TI quite a lot. The only gotcha is that
they don't like ceramics at the output. So either go for tantalum or a
0.5 Ohm series resistor + ceramic. When looking for input voltages

12V the choices get very limited though.

--
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico@nctdevpuntnl (punt=.)
--------------------------------------------------------------

 

[Joerg]

Tim Wescott wrote:

On Thu, 17 Nov 2011 13:51:35 -0600, krw@att.bizzzzzzzzzzzz wrote:

On Thu, 17 Nov 2011 13:18:21 -0600, Tim Wescott <tim@seemywebsite.com
wrote:

24V --> 3.3V, around 250mA, good enough for digital.

There are a bazillion out there -- it seems like anyone who even
pretends to sell analog circuit parts sells these, with a wide variety
of price ranges, features, etc.

So -- who do you think is best, and why? I'm mostly looking for parts
that actually work the way that the data sheet says they will, and that
don't have any really bad "gotchas". If anyone has been particularly
bad about supply hiccups -- mention that, too.
LTC, if you can afford them. Simulation is a big factor. I've had good
luck with TI, too.

LT certainly is nice. I had a National apps engineer tell me flat out
that they didn't have behavioral SPICE models of their switching
controllers, and that I should just use their web tool -- which lead me
to tell him flat out that National had just lost a sale (had I been doing
something exactly in line with what the regulator was designed for I may
have had a different answer -- but I still didn't like the attitude of
"oh just use our design tools, you don't actually have to understand what
our products do").

Just for kicks I had used Webbench on a few of my projects. Every single
one of them came back as impossible to build. Yet oodles of them have
come out of various production facilities over the years

--
Regards, Joerg

http://www.analogconsultants.com/

 

[John Miles, KE5FX]

On Nov 17, 11:47 am, Fred Bloggs <bloggs.fredbloggs.f...@gmail.com>
wrote:

On Nov 17, 2:18 pm, Tim Wescott <t...@seemywebsite.com> wrote:

24V --> 3.3V, around 250mA, good enough for digital.

There are a bazillion out there -- it seems like anyone who even pretends
to sell analog circuit parts sells these, with a wide variety of price
ranges, features, etc.

So -- who do you think is best, and why?  I'm mostly looking for parts
that actually work the way that the data sheet says they will, and that
don't have any really bad "gotchas".  If anyone has been particularly bad
about supply hiccups -- mention that, too.

--www.wescottdesign.com

NS is #1 in performance in every product line they produce.

That's an interesting assertion, to say the least.

-- john

 

[Martin Riddle]

"Tim Wescott" <tim@seemywebsite.com> wrote in message
news:YpydnYZckPBgwFjTnZ2dnUVZ_g6dnZ2d@web-ster.com...

24V --> 3.3V, around 250mA, good enough for digital.

There are a bazillion out there -- it seems like anyone who even
pretends
to sell analog circuit parts sells these, with a wide variety of price
ranges, features, etc.

So -- who do you think is best, and why? I'm mostly looking for parts
that actually work the way that the data sheet says they will, and
that
don't have any really bad "gotchas". If anyone has been particularly
bad
about supply hiccups -- mention that, too.

--
www.wescottdesign.com

The Simple switchers from NS are good for 24v input. Just watch for
spikes as that will take out the input protection diode.
Not may others go to 24v.

Cheers

 

[Phil Hobbs]

On 11/17/2011 2:47 PM, Fred Bloggs wrote:

On Nov 17, 2:18 pm, Tim Wescott<t...@seemywebsite.com> wrote:
24V --> 3.3V, around 250mA, good enough for digital.

There are a bazillion out there -- it seems like anyone who even pretends
to sell analog circuit parts sells these, with a wide variety of price
ranges, features, etc.

So -- who do you think is best, and why? I'm mostly looking for parts
that actually work the way that the data sheet says they will, and that
don't have any really bad "gotchas". If anyone has been particularly bad
about supply hiccups -- mention that, too.

--www.wescottdesign.com

NS is #1 in performance in every product line they produce.

You're out of your mind. The late lamented National made the noisiest
op amp in every single class, and never got over the notion that 1 mV
was a good enough offset spec, or that 400 ns was a fast settling time.

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
845-480-2058

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

 

[Phil Hobbs]

On 11/17/2011 10:42 PM, Fred Bloggs wrote:

On Nov 17, 10:04 pm, Phil Hobbs
pcdhSpamMeSensel...@electrooptical.net> wrote:
On 11/17/2011 2:47 PM, Fred Bloggs wrote:

On Nov 17, 2:18 pm, Tim Wescott<t...@seemywebsite.com> wrote:
24V --> 3.3V, around 250mA, good enough for digital.

There are a bazillion out there -- it seems like anyone who even pretends
to sell analog circuit parts sells these, with a wide variety of price
ranges, features, etc.

So -- who do you think is best, and why? I'm mostly looking for parts
that actually work the way that the data sheet says they will, and that
don't have any really bad "gotchas". If anyone has been particularly bad
about supply hiccups -- mention that, too.

--www.wescottdesign.com

NS is #1 in performance in every product line they produce.

You're out of your mind. The late lamented National made the noisiest
op amp in every single class, and never got over the notion that 1 mV
was a good enough offset spec, or that 400 ns was a fast settling time.

Cheers

Phil Hobbs


That's just their ultra conservative specification system.

You're out of your mind again. NS made the noisiest op amps on the
planet. I was always a National fan, having learned a lot of circuit
design from their app notes when I was in grade school back in the '70s,
but that didn't blind me to their faults. (I still have a dozen or so
LH0063 "Damn fast buffer amplifiers" in my drawer. Best data sheet _ever_.)

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
845-480-2058

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

 

[Fred Bloggs]

On Nov 17, 10:04 pm, Phil Hobbs
<pcdhSpamMeSensel...@electrooptical.net> wrote:

On 11/17/2011 2:47 PM, Fred Bloggs wrote:

On Nov 17, 2:18 pm, Tim Wescott<t...@seemywebsite.com>  wrote:
24V -->  3.3V, around 250mA, good enough for digital.

There are a bazillion out there -- it seems like anyone who even pretends
to sell analog circuit parts sells these, with a wide variety of price
ranges, features, etc.

So -- who do you think is best, and why?  I'm mostly looking for parts
that actually work the way that the data sheet says they will, and that
don't have any really bad "gotchas".  If anyone has been particularly bad
about supply hiccups -- mention that, too.

--www.wescottdesign.com

NS is #1 in performance in every product line they produce.

You're out of your mind.  The late lamented National made the noisiest
op amp in every single class, and never got over the notion that 1 mV
was a good enough offset spec, or that 400 ns was a fast settling time.

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
845-480-2058

hobbs at electrooptical dot nethttp://electrooptical.net

That's just their ultra conservative specification system.

 

[John S]

On 11/17/2011 5:31 PM, John Miles, KE5FX wrote:

On Nov 17, 11:47 am, Fred Bloggs<bloggs.fredbloggs.f...@gmail.com
wrote:
On Nov 17, 2:18 pm, Tim Wescott<t...@seemywebsite.com> wrote:

24V --> 3.3V, around 250mA, good enough for digital.

There are a bazillion out there -- it seems like anyone who even pretends
to sell analog circuit parts sells these, with a wide variety of price
ranges, features, etc.

So -- who do you think is best, and why? I'm mostly looking for parts
that actually work the way that the data sheet says they will, and that
don't have any really bad "gotchas". If anyone has been particularly bad
about supply hiccups -- mention that, too.

--www.wescottdesign.com

NS is #1 in performance in every product line they produce.

That's an interesting assertion, to say the least.

-- john

Spehro came up with this one. It's apropriate...

http://i.imgur.com/lHPEn.jpg

 

[Vladimir Vassilevsky]

Tim Wescott wrote:

24V --> 3.3V, around 250mA, good enough for digital.

This is trivial. Either one would work.

ST is inexpensive and dull, LT is the nice but expensive, MAXIM is good
except for that is from MAXIM, the others are somewhere in between.

There are a bazillion out there -- it seems like anyone who even pretends
to sell analog circuit parts sells these, with a wide variety of price
ranges, features, etc.

So -- who do you think is best, and why? I'm mostly looking for parts
that actually work the way that the data sheet says they will,

What planet are you from?

and that
don't have any really bad "gotchas". If anyone has been particularly bad
about supply hiccups -- mention that, too.

If a regulator has ENABLE or SHUTDOWN pin, check the voltage range for
this pin. Some are rated to Vin, the others to Vout or +5V or such.
Over/under voltage causes weird effects.

If you need to synchronize the regulator to external clock, this is special.

Super efficient, minimum dropout, super low EMI or minimum questient
current is special, too.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com

 

[Gerhard Hoffmann]

On 11/18/2011 12:31 AM, John Miles, KE5FX wrote:

On Nov 17, 11:47 am, Fred Bloggs<bloggs.fredbloggs.f...@gmail.com

NS is #1 in performance in every product line they produce.

That's an interesting assertion, to say the least.

If you are after low phase noise (and methinks you are),
then some of their CLC-family CFB Opamps are hard to beat.

And they have really nice _fast_ ADCs.

73, Gerhard

 

[Spehro Pefhany]

On Fri, 18 Nov 2011 10:30:30 +0100, the renowned Gerhard Hoffmann
<dk4xp@arcor.de> wrote:

On 11/18/2011 12:31 AM, John Miles, KE5FX wrote:
On Nov 17, 11:47 am, Fred Bloggs<bloggs.fredbloggs.f...@gmail.com

NS is #1 in performance in every product line they produce.

That's an interesting assertion, to say the least.

If you are after low phase noise (and methinks you are),
then some of their CLC-family CFB Opamps are hard to beat.

And they have really nice _fast_ ADCs.

73, Gerhard

Indeed. 12-bit 3.2GSPS (interleaved mode). (with 100kRad version
available)


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

 

[Rich Webb]

On Thu, 17 Nov 2011 13:18:21 -0600, Tim Wescott <tim@seemywebsite.com>
wrote:

24V --> 3.3V, around 250mA, good enough for digital.

There are a bazillion out there -- it seems like anyone who even pretends
to sell analog circuit parts sells these, with a wide variety of price
ranges, features, etc.

So -- who do you think is best, and why? I'm mostly looking for parts
that actually work the way that the data sheet says they will, and that
don't have any really bad "gotchas". If anyone has been particularly bad
about supply hiccups -- mention that, too.

It depends on what the meaning of 24V is. For operating on a shipboard
24V DC bus (Unclean! Unclean!) we generally go with a string of fuses,
transorbs, & filters into a potted module from, e.g., GAIA (MGDSI-04)
down to 5V, and then a linear to bring that down to a quiet Vdd for the
processor. The 5V bus also goes to the less demanding components.

--
Rich Webb Norfolk, VA