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Old 14th September 2013, 06:00 PM   #21
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In my local shop TL431 is available only in TO92 package so board space should be no problem at all.
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Old 14th September 2013, 06:05 PM   #22
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Yes, I figured that out, thanks for the replies! But it still needs 2 additional resistors.

I will see whether I can easily get LM329's and if not (or costly) I will search for the TO-92 TL431. And maybe just a simple zener will work, for the original Sulzer regulator it seems it did.
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Old 15th September 2013, 02:23 PM   #23
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As far as voltage reference stability is concerned, how good is a zener?

For example, I can use a 5.1V zener in series with a 820Ω resistor. I need 9V output, so that should give about (9-5.1)/820 = 4.76mA of current through the zener.

How stable will this setup be? Noise will be quite easily filtered, I just want to know how it will typically perform.

Why use this setup? It can't get any more simple or cheap. But I am looking for output variations of 1-2% max. Will this suffice?
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Old 15th September 2013, 02:40 PM   #24
jcx is offline jcx  United States
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LM329 have active shunt regulator circuitry lowering the (DC-1kHz) dynamic impedance of the internal buried Zener to < 1 Ohm at any current within its operating spec

true Zener's are crap - have poor dynamic Z, broad "knee" require lots of current

above ~6 Vz rated "Zener diodes" Avalanch mode takes over - gives sharper knee, better Z at lower curernts

read some data sheets - look for tutorials or app notes if you don't understand the specs impact on circuit performance

Last edited by jcx; 15th September 2013 at 02:47 PM.
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Old 27th September 2013, 12:39 PM   #25
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The thing is that I want to use one single component as reference. A TO-92, or a diode package.

Since LM329 is not easily sourced these days, can anyone propose a modern equivalent? A fixed voltage precision reference that will not cost a fortune?
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Old 27th September 2013, 12:58 PM   #26
RJM1 is offline RJM1  United States
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Take your pick.
Linear Technology - Parametric Search for Series Voltage References
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Old 27th September 2013, 01:00 PM   #27
DUG is offline DUG  Canada
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Do you buy from Digi-Key?

Digi-Key results

5V, TO-92, under $1 (US) 3 at 1% and 2 at 0.5%

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Old 27th September 2013, 01:05 PM   #28
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Prior postings here many years ago concluded that true zeners were very noisy, and that as long as you were far removed from the true zener voltage of ca 5.6V then it didn't matter much if you used zeners or LED's. Since then I suspect but I don't know this to be fact, that band gaps have taken over completely in the semiconductor industry. Don't know how good they are.
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Old 27th September 2013, 01:08 PM   #29
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Thank you for your answers!

DUG, I haven't bought anything yet, but seems like I will. I have an electronic store close to me that implements orders from there if I want so. Do you think that ordering directly will come cheap?

EDIT: LM336 seems good and cheap. Has anyone had any experience with it?

Last edited by audiostrat; 27th September 2013 at 01:12 PM.
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Old 27th September 2013, 10:56 PM   #30
DUG is offline DUG  Canada
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Quote:
Originally Posted by audiostrat View Post
Thank you for your answers!

DUG, I haven't bought anything yet, but seems like I will. I have an electronic store close to me that implements orders from there if I want so. Do you think that ordering directly will come cheap?

...
I really have no idea how much this stuff costs in Greece.

Use the Digi-key part search and narrow down the selection with what features you want.
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