Alw,Jan didden, Guido please help with TL431

[kimschips]

Hello all.

I am about to decide how to connect a Tl431 based psu to my new dac project. (3.3V for the digital section)
Cs8416->AD1896-> 2 PCM1798 dacs

First connection

http://peufeu.free.fr/audio/extremi...mplement_2.html

Here we got a choke to separate each TL431 based psu for the digital section in the dac and tL431 is // coupled with small ceramic capacitors+10uF Oscon.

Do you think TL431 is stable when it´s directly coupled with such small values?

Or is it better to do it this way:

LM337->CCS->TL431//22uF Oscon->47uH inductor->ceramic 10nF +100nF?

Or:
LM337->CCS->TL431//22uF Oscon->47uH inductor-> 22uF BG-NX-HQ//100NF Rifa phe426??

Any suggestions for a small local psu and decoupling for the Dacs VD and VA supply?

Best regards
Thanks for all

Kim

[Guido Tent]

Originally posted by kimschips
Hello all.

I am about to decide how to connect a Tl431 based psu to my new dac project. (3.3V for the digital section)
Cs8416->AD1896-> 2 PCM1798 dacs

First connection

http://peufeu.free.fr/audio/extremi...mplement_2.html

Here we got a choke to separate each TL431 based psu for the digital section in the dac and tL431 is // coupled with small ceramic capacitors+10uF Oscon.

Do you think TL431 is stable when it´s directly coupled with such small values?

Or is it better to do it this way:

LM337->CCS->TL431//22uF Oscon->47uH inductor->ceramic 10nF +100nF?

Or:
LM337->CCS->TL431//22uF Oscon->47uH inductor-> 22uF BG-NX-HQ//100NF Rifa phe426??

Any suggestions for a small local psu and decoupling for the Dacs VD and VA supply?

Best regards
Thanks for all

Kim

Hi Kim

The link does not work (today). So far I used the 431 with a variety of caps between 100nF and 47uF.

To separate the regs, us ferrites. Your last config looks OK. I like wima MKS2 (100nF). I would not paralle the BG's with anything else.

Ans last but not least, try and listen what you like.

bes

PS: The equivalent noise is 100nV/SqrrtHz so a 5V ouitput would give 200nV/SqrrtHz, not super quiet.....

[peranders]

Notice that Texas TL431 has noise at 48 nV/Hz, best brand so far.

[Guido Tent]

Originally posted by peranders
Notice that Texas TL431 has noise at 48 nV/Hz, best brand so far.

Ah, didn't compare the all, so thanks for the hint

Still noisy compared to other references, but these need a whole circuit around them, whilst a 431 is an easy and reliable soulution.

Not reccomend for best clock performance........

[jcx]

http://www.cirrus.com/en/pubs/appNote/an04.pdf

fig 12 shows tl part as adc ref, table puts its performance in perspective with other good references

can find good bypass decoupling hints in other ref circuits shown

[peranders]

Originally posted by Guido Tent
Not reccomend for best clock performance........

What do you recommend then?

I checked the document mentioned above and it's interesting to see how noise in the reference influences the S/N, see last page.

[kimschips]

Hello all

Thanks for your input

The link is here, should work now, please comment the TL431 setup

http://peufeu.free.fr/audio/extremis...plement_2.html

The setup is thought like this, because LM337+CCS or any other preregs shall be on a separate board, so people who want´s the new Dac board( when it´s finnish) can tweak and change supply after their wishes goals.


Please make some suggestions if you had a other solution for decoupling and local psu by the digital chips

Best regards
Kim

[Guido Tent]

Originally posted by peranders

What do you recommend then?

lower noise

[Guido Tent]

Originally posted by kimschips
Hello all

Thanks for your input

The link is here, should work now, please comment the TL431 setup

http://peufeu.free.fr/audio/extremis...plement_2.html

Please make some suggestions if you had a other solution for decoupling and local psu by the digital chips

Best regards
Kim

Hi Kim

This link works, indeed

Mr Peufue already refers to my document, so no additional remarks made.....

best

[peranders]

How low noise do you recommend achieved by what?