The simplistic Salas low voltage shunt regulator

[Salas]

The RC Zobel is local termination to the Bib and should stay local to the bib. If it can be close enough to both on dual role for decoupling the 1541 too, so much to the better. But is a 4u7 plastic capacitor enough for that chip?

[massimo]

Originally Posted by studiostevus

Thanks! I will be using BiB.

As my supplies used to be off-board, I had some decoupling caps very (3 mm) close to the supply pins of the TDA1541 (1 uF SMD film + 33uF BG + 270uF Oscon SEPC). Now that I will be placing the shunt regulators on the same pcb as the dac circuit, how can I best arrange this decoupling?

The BiB uses 2 caps on the output (part of the Zobel). Should I just place these caps very close to the chip and omit the decoupling caps I use now? OR should I use the caps on the output of the supply reg and in addition use a decoupling cap close to the chip? OR should I use the current decoupling caps as a replacement for the zobel caps of the shunt reg?

Salas already suggested to put a 100 ohm resistor at the output of the shunt reg when other decoupling caps are present close to the ICs.

I would leave the output El cap OR the Zobel (MKT+ R) close to the shunt device (BJT or MosFet)

[massimo]

Sorry Salas, we were writing a reply at the same time!

[studiostevus]

Originally Posted by massimo

Salas already suggested to put a 100 ohm resistor at the output of the shunt reg when other decoupling caps are present close to the ICs.

.. forming an RC filter??

If I understand correctly, this is the schematic
Screen shot 2011-11-04 at 8.57.04 PM.png

[Salas]

Yes, but no C26. That one is the ''plan B'' capacitor in the Bib.

[studiostevus]

Originally Posted by Salas

Yes, but no C26. That one is the ''plan B'' capacitor in the Bib.

So the electrolyte is "plan B", the MKT is standard?

[studiostevus]

As far as I could read earlier in the thread, the BJT version is recommended for high frequency circuits, so I would use that for my 11 MHz clock.

For the inputs on the DAC (digital, analog and analog/digital), is there a recommendation on which version to use? Certainly MOSFET for the analog supply to the chip for lowest Zo.... The digital circuits are probably better off with the bjt-version...?

[Salas]

Originally Posted by studiostevus

So the electrolyte is "plan B", the MKT is standard?

Yes, its role is described in the guide in appendix 4. Did you read the 1.1 Bib guide?

[Salas]

Originally Posted by studiostevus

As far as I could read earlier in the thread, the BJT version is recommended for high frequency circuits, so I would use that for my 11 MHz clock.

For the inputs on the DAC (digital, analog and analog/digital), is there a recommendation on which version to use? Certainly MOSFET for the analog supply to the chip for lowest Zo.... The digital circuits are probably better off with the bjt-version...?

Also a big C101 polar cap value is recommended when applied on clocks. Due to sensitivity in 1/f noise of those circuits. Your other choices are good.

[Joshua_G]

Originally Posted by Salas

Also a big C101 polar cap value is recommended when applied on clocks. Due to sensitivity in 1/f noise of those circuits. Your other choices are good.

Hi Salas,
Is BJT 1/f noise lower than MOSFET?