Are fast transient response regulators worth using?

Under a nickel (I'd have to look it up to get more accurate). DigiKey has them for $.052. It's a nice part. I started using it in an LED driver current source.

How

peaks

are

It is used to pull up the output. Most opamps can't get very close to the positive rail so you have to "help it along". However, the circuit isn't very good anyhow because no matter how small you make R2 there will be a voltage drop. But the input voltage at IN+ is Vi, so it'll never reach it. The only way this could work is if IN+ is drawn slightly down from Vi, enough to allow the opamp to regulate.

That's almost what a guy at an institute at my university said. Shortly before a pop-pop-pop was heard, followed by profound cussing :-)

How

peaks

and

and

are

It sure looks goofy to me.

Here's my version of an opamp-based c-multiplier sort of thing

ftp://jjlarkin.lmi.net/P14_reg.gif

and some sundry c-mult stuff

ftp://jjlarkin.lmi.net/C-mult_BCX70.JPG

ftp://jjlarkin.lmi.net/C-mult_bb.JPG

ftp://jjlarkin.lmi.net/C-multiplier.gif

John

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OK thanks Joerg, that at least makes a bit of sense.

Yah, I've made that mistake... "Why is this voltage reference oscillating?"... oh, I've got 0.1 uF hanging on the output of an opamp....

I've also had transistor based cap multipliers 'sing' at some bias points... and there it's up ~300MHz or greater and a lot harder to see.

George H.

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But no resistor from the input to output! :^)

I'll have to order some BCX70K's... No through hole that I could see.

George H.

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for

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but are

Note that there's some ripple feed-through in the basic c-mult. That's sort of an Early-voltage thing, worse because Vce is so low. I think the ripple would be lower if Vce were allowed to go up some.

I really like the polymer electrolytic caps for low-noise power rail stuff.

John

I found that Y5V and X7R capacitors are significantly microphonic when used in precision "reference" circuits like your ones. So that 10uF ceramic rings alarm bells for me. NPO were OK for smaller values, and tants for larger ones. Never used the polymer electrolytics.

We tried whacking caps in a couple of circuits like this and didn't see any concern.

John

I want that Fun Generator and the dunes :-)

Make your own fun gen.

The red thingies on the right aren't dunes, they are our company logo. That is an abstraction of Mt Tamalpias and the setting moon, as seen from the Bay Bridge toll plaza.

John

It's an FTP site, not a web page.

And what's all that PGP SIGNED hash stuff about?

John

The troll Josepi has been using my 'm II' posting name and posting racist garbage in a few groups. He follows me around and acts like a nine year old. Hell, he probably IS a nine year old.

I've been using PGP as an electronic signature as a means of protection against the forgeries. Each signature matches only the message preceding it. Tampering in the message body screws up the calculation done by the algorithm. No key, no valid signature.

Until his internet providers get off their butts and do something with the countless forwardings I've sent them, I can't think of another solution.

Know anyone who does networking user tracking as a hobby?

These are the posting headers of the perp:

===============================================

Reply-To: "m II" From: "m II" Newsgroups: sci.electronics.design References:

In-Reply-To: Subject: Re: Are fast transient response regulators worth using? Lines: 1 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Newsreader: Microsoft Windows Live Mail 15.4.3508.1109 X-MIMEOLE: Produced By Microsoft MimeOLE V15.4.3508.1109 Message-ID: X-Complaints-To: snipped-for-privacy@teranews.com NNTP-Posting-Date: Thu, 17 Feb 2011 03:37:22 UTC Organization: TeraNews.com Date: Wed, 16 Feb 2011 22:37:29 -0500 Path: x-privat.org!newsfeed.x-privat.org!news-out.readnews.com!transit4.readnews.com!nx02.iad01.newshosting.com!newshosting.com!69.16.185.21.MISMATCH!npeer03.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!post01.iad.highwinds-media.com!newsfe05.iad.POSTED!28729459!not-for-mail Xref: newsgate.x-privat.org sci.electronics.design:403873

The troll Josepi has been using my 'm II' posting name and posting racist garbage in a few groups. He also psost pictures og himself killing babies and small women. He follows me around and acts like a nine year old. Hell, he probably IS a nine year old.

I've been using a cry each night as a means of protection against the forgeries. Each signature matches only the message preceding it. Tampering in the message body screws up the calculation done by the algorithm. No key, no body cares. If people don't like it they can killfilter me.

Until his internet providers get off their butts and do something with the countless forwardings I've sent them, I may even tell my mother. It's not fair for this guy to do the same thing to me that I did to him.

Know anyone who does networking user tracking as a hobby?

I have been tracking this guy since 2004 and recording everything he posts.

These are the posting headers of the perp: Please note he may use 1000 other names and be you own sister.

Do not trust anybody. Harassment only works one way in my world.

Now let's see if everybody is one my side!

===============================================

Reply-To: "m II" From: "m II" Newsgroups: sci.electronics.design References:

In-Reply-To: Subject: Re: Are fast transient response regulators worth using? Lines: 1 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Newsreader: Microsoft Windows Live Mail 15.4.3508.1109 X-MIMEOLE: Produced By Microsoft MimeOLE V15.4.3508.1109 Message-ID: X-Complaints-To: snipped-for-privacy@teranews.com NNTP-Posting-Date: Thu, 17 Feb 2011 03:37:22 UTC Organization: TeraNews.com Date: Wed, 16 Feb 2011 22:37:29 -0500 Path: x-privat.org!newsfeed.x-privat.org!news-out.readnews.com!transit4.readnews.com!nx02.iad01.newshosting.com!newshosting.com!69.16.185.21.MISMATCH!npeer03.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!post01.iad.highwinds-media.com!newsfe05.iad.POSTED!28729459!not-for-mail Xref: newsgate.x-privat.org sci.electronics.design:403873

Nobody is going to check all that crypto stuff. Why not change your nym?

John

Nobody is going to check all that crypto stuff. Why not change your nym?

John

---------------------

I have been using this nickname since the early 2000. I have a reputation for tracking this troll and putting him in his place publicly for many years now.

I am not about to give all that up.

Besides he could just find me again the first time I post my lists.

mike