Kosmo 1222 source a reasonable LM4040AIZ 4.1?

Hi Im going through the Kosmo 1222 BOM and I cant find a reasonable LM4040AIZ 4.1
I can find a LM 4040 BIM3-4.1 in SOT-23-3 format.
or a LM 4040 CIZ-5.0 5 V TO-92

The guy link on the BOM is an ebay seller.
with the following status.
This seller is currently away, and isn’t processing orders at this time. You can add this item to your Watch list to keep track of it.
and it will cost me 17 euros to get 1 of them ( im thinking of getting parts for 3 oscilators).

I have gone for a set of 6 LM4040DIZ-4.1 @ €7.40 for 6.
Presume they will work?

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you can compare to see if it’s compatible :


i don’t know
I also find it difficult to find this component

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The first letter after the type code is the tolerance grade:

  • Max 0.1%, 100 ppm/°C – A Grade
  • Max 0.2%, 100 ppm/°C – B Grade
  • Max 0.5%, 100 ppm/°C – C Grade
  • Max 1.0%, 150 ppm/°C – D Grade

Datasheet mentions an E Grade too (2.0%) but not sure if that’s still produced.

ok by that logic I should go for the LM 4040 BIM3-4.1 in SOT-23-3 as it is more accurate.
Even thought I have to solder a surace mount component.
Ill get them both and see what works.

Thanks for the feedback. :slight_smile:

oof, i was getting mine at Digikey, but they seem to be down right now :\

not really reasonable… but

https://www.mouser.com/ProductDetail/Texas-Instruments/LM4040AIZ-41-NOPB?qs=sGAEpiMZZMuBck1X%2B7j9fFxOFMTVQaIHYpdxjwI90Yw%3D

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thanks a lot ! …

I second Mouser. For my first LMNC Oscillator, I bit the bullet for one on eBay for £7.99 and 80p shipping, then saw them on mouser for so much cheaper, and I kicked myself in the foot. Safe to say I’ll be more thoroughly researching for components now!

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Well, of course, one from Mouser and nothing else will run you close to $9 (in the US) once you factor in shipping.

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It’s one of the harder to find parts for LMNC modules like the momentary switches for the ADSR. I think I ended up getting the AIZ from mouser. That being said other pcb kits like mfos use way more parts you can’t find on Tayda

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When I got mine I got a few thousand resistors as well so I wouldn’t feel bad about paying more in shipping than the parts :rofl:

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for me on Mouser 20E for shippement !?! crazy
I’m skipping my turn and wait to find another source

i just find some LM4040 but DIZ 4.1 on ebay but i don’t know if this tolerance (1.0%) make a big difference ?

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with the trim pot on the output of that regulator i would think it really shouldn’t make all that much difference. Unless that AIZ is just that much more stable

1% of 4.1 is only +- 0.041v

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yes ! it’s maybe the simplest solution for me without breaking the bank :grinning:

(the AIZ = 0.1%)

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In our application (the #1222), as you say the precision doesn’t matter thanks to the REF trim pot.
The main difference between the A, B & C parts and the D&E, is the temperature stability (±100ppm/°C vs ±150ppm/°C), but if you intend to keep the temperature mostly constant or are willing to re-tune when temperature changes significantly, it probably doesn’t matter all that much.

If my calculations are correct, the difference isn’t huge.
If you had a worst case of going from 0°C in a van to 45°C in a concert like Sam had:
The change in voltage would be ±100ppm/°C x 45°C = ±4500ppm
For the top octave at 4V, you get a drift of ±4500/1000000x4V= 0.018V
In musical terms, that is 0.018 octave x 12 semitone/octave x 100 cent/semitone = 21.6 cents
For the D&E parts, multiplying by 1.5 gives us 32.4 cents

Chances are that with such a large temperature change, you may need a tuning anyways due to other components’ temperature coefficient.

EDIT: I had missed the factor of 4 for the top octave in the first multiplication.

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thanks a lot for these presisions !

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I think I must have the wrong one, like totally wrong…

Is there an equivilrnt… ( off to look )

Here’s another question, does that device have enough current capacity to provide the reference for 3 modules?? seems it would reduce cost if you could get one module to provide the reference for a string of them. Or would there be a licklyhood of voltage drop from one pcb to the next?

Thanks

Rob

…which makes me wonder if a TL431 wouldn’t be a better choice (<50 ppm/°C avg, and ~1/3 of the price) but that one would depend on a resistor divider to give you 4.0 V, but assuming the resistors have the same tempco as each other that shouldn’t matter much, and the other circuit has a trimmer too, and you can use the trimmer as the divider, and… decisions, decisions.

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Is there a reason, and I may be missing something entirely…

That a high precison 5v regulator could not be used on it’s own, and the resistor divider ladder just added to with an extra 10k Pre-Precision resistor. or the 1st 10K swapped out for a 20K?

Rob