Reducing noise in voltage regulators - Page 12

jwb · 19th March 2003, 05:50 PM

Heh, I'm waiting for the first guy to jump in and say "jwb -- you are a huge moron!". I just don't understand electricity before I've had my first cup of coffee. I should remember that before I start typing into this little box.

I shall try to redeem myself. C3 and R3 form a <em>high-pass</em> filter, not a low-pass. They ensure DC stability below 11HZ The op-amp is internally compensated, we don't need to worry about HF stability.

lopan · 27th November 2004, 11:42 AM

OK, If I have a very, very clean +-12 volt DC supply and I need to pull it down to 8.5 to 8.9 volts DC should I use the 1086 and 1186 as I already have these or is there a Zener that will set the output in the range stated above. Thanks

mlloyd1 · 28th June 2005, 08:05 PM

since there is interest in these things from time to time, here is YALNR.

Courtesy of Maxim (so you know who's chips it uses

) from latest EDN, which, BTW, is a pretty good trade rag.

http://a330.g.akamai.net/7/330/2540/...es/62305di.pdf
(last two pages)

amplifierguru · 29th June 2005, 01:58 AM

Pretty ordinary - appears dominated by the op amp noise which is > 4.5nV/sqrt Hz.

Hi jwb,

have you considered a nested FB loop using 2 op amps to find some gain at 25MHz. Only the first needs to be ultra low noise.
If it's commercial I may let you use my integrator nesting concept which has been patented by others but I have established prior art.

Is DC drift of the reference a concern?

Greg

pINO · 28th November 2006, 07:47 AM

Hi Andy,

I'm sorry to bother you in this old thread. I've just found this thread. In Your Post #20, Is it possible to improve this regulator by adding a small cap multiplier on NE5534 pos supply to replace R2 & C2 network?

pINO

28th November 2006, 07:47 AM	#115
pINO diyAudio Member Join Date: Jul 2004 Location: Jakarta	Andy's Sulzer Schematic Hi Andy, I'm sorry to bother you in this old thread. I've just found this thread. In Your Post #20, Is it possible to improve this regulator by adding a small cap multiplier on NE5534 pos supply to replace R2 & C2 network? pINO __________________ pINO

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19th March 2003, 05:50 PM	#111
jwb diyAudio Member Join Date: Mar 2002 Location: San Francisco, USA	Heh, I'm waiting for the first guy to jump in and say "jwb -- you are a huge moron!". I just don't understand electricity before I've had my first cup of coffee. I should remember that before I start typing into this little box. I shall try to redeem myself. C3 and R3 form a <em>high-pass</em> filter, not a low-pass. They ensure DC stability below 11HZ The op-amp is internally compensated, we don't need to worry about HF stability.

27th November 2004, 11:42 AM	#112
lopan diyAudio Member Join Date: Sep 2004 Location: California	OK, If I have a very, very clean +-12 volt DC supply and I need to pull it down to 8.5 to 8.9 volts DC should I use the 1086 and 1186 as I already have these or is there a Zener that will set the output in the range stated above. Thanks

28th June 2005, 08:05 PM	#113
mlloyd1 diyAudio Member Join Date: Feb 2001 Location: illinois	since there is interest in these things from time to time, here is YALNR. Courtesy of Maxim (so you know who's chips it uses ) from latest EDN, which, BTW, is a pretty good trade rag. http://a330.g.akamai.net/7/330/2540/...es/62305di.pdf (last two pages)

29th June 2005, 01:58 AM	#114
amplifierguru Account Disabled Join Date: Aug 2004 Location: Earth	Pretty ordinary - appears dominated by the op amp noise which is > 4.5nV/sqrt Hz. Hi jwb, have you considered a nested FB loop using 2 op amps to find some gain at 25MHz. Only the first needs to be ultra low noise. If it's commercial I may let you use my integrator nesting concept which has been patented by others but I have established prior art. Is DC drift of the reference a concern? Greg

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