Cs8412

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#21
MKS 220 nF is OK at that spot ( edited my post because I read FKP at first which are real fine ). Don't know the other type you mention but they seem fine with useable 5 mm pitch. Never had problems with polystyrene in these applications although that might sound a bit stupid ( no problems does not necessarely mean OK ). Lots of quality tuners with polystyrene in it and it isn't real RF in this application, isn't it ?

I can very well be very wrong but polystyrene is good at RF IMO. Please correct me if I am wrong.
 
#24
Cheers- You have cleared-up a lot of my confusion.

220nF MKS 02
&
3300pF Polystyrene

I must confess that I am currently using some old capacitors from my components tray and the result is excellent:

Philips MKT 344 series for 220nF (polyester)

Capacitor marked 3300 100-A Wima X8 (who knows)

What is so good about MKT- are these better than MKS?
 
#25
Wildmonkeysects Loopfilter Components

Oli said:
Cheers- You have cleared-up a lot of my confusion.

220nF MKS 02
&
3300pF Polystyrene

I must confess that I am currently using some old capacitors from my components tray and the result is excellent:

Philips MKT 344 series for 220nF (polyester)

Capacitor marked 3300 100-A Wima X8 (who knows)

What is so good about MKT- are these better than MKS?
Click to expand...

Hi Oli,
For what it is worth I am using:
3n3 ceramic
0.22µF polypropylene and
470 Ohm metalfilm.
😎
 
#26
Ceramic 3.3 nF is an option but make it an SMD soldered directly to the pins then. In fact that is one of the best options but I don't know your skills with SMD caps. With too big caps for the 3.3 nF and/or too long wires the effect of Monkeysects filter is less then optimal. These are sensitive pins.

AFAIK MKS is the same as MKT.
 
#27
Interesting link on PLL capacitor choice

I have just found some interesting information:

Rules of Thumb for Choosing Loop Filters

Loop Filter Capacitors

This link suggests the use of ceramic capacitors: NP0 or C0G

It is suggested that X7R is best avoided

Perhaps Elso's setup is ideal:

3300pF = C0G/NP0 ceramic
220nF = Film

I am still unsure about the 220nF film choice-

I can obtain polypropylene at 15mm lead pitch or the aforementioned 5mm pitch polyester.

The polyester offers a shorter loop, but with a poorer dielectric
The polypropylene offers a great dielectric but a longer loop

Q. Is the loop length for the 220nF capacitor so critical?

Q. Which type of 220nF film capacitor do I use?
 
#28
So use a quality ceramic SMD or small type ( NP0 or C0G indeed ) for the 3.3 nF directly on the pins and MKT or MKP for the 220 nF but keep it very compact when using CS8412. Keeping it compact with MKT will be better than standard layout with the best caps you can find. 15 mm length in stead of 5 mm makes a difference in compactness/loop length. With CS8412 this is important. Did you read Monkeysects recommendations, he explained *all* of this ?
 
#29
Wima MKS02 polyester better than an NP0/G0G?

Cheers Jean-Paul-

I have read some info about the Wildmonkeysects loop filter but didn't spot the detail about choice of capacitor in the info that I read.

Anyhow thanks for answering my question.

i have recently become confused about film capacitors versus ceramic capacitors-

For a given lead pitch are polyester and polypropylene film capacitors better than NP0/C0G?

Wima MKS02 polyester has 2.5mm lead pitch- would this be better than an equivalent sized NP0/G0G?

Note: I am not using SMD on this project
 
#31
Buy a few and measure them. You can kindly ask if you may use the equipment at the shop to measure the stuff you want to buy. Or bring your own multimeter/capacitancemeter. No problem in general ( except for wanting to do this with semiconductors ).
 
#32
True, I could measure them

That's a good point-

I can simply measure the capacitance of a number of the polyester capacitors and 'pick a good one'.

Is the polyester a better dielectric than NP0/C0G?
(for identical physical dimensions)
 
#33
I believe I can now answer my own question

I believe I can now answer my own question:

Polyester:

"Typical applications would be where you want a capacitor larger than a C0G but better electrical properties than an X7R."

Here is the link containing the information:

Film Capacitors

In summary:

3300pF = COG
220nF = Polyester

🙂
 
#34
For PLL loop filter design, use surface mount C0G/NPO capacitors. If the values in question are small and you've got room on your PCB, you could try some surface mount mica caps... but they're a little bit on the pricy side and difficult to get.

I wouldn't use large leaded polystyrenes... at the frequencies that audio PLLs run at, they're likely to behave more like inductors than capacitors. X7R is acceptable, but only if the voltage rating on them is high in comparison to the voltage you're running them at, to minimise the voltage coefficient on them.

Push the main (FILT pin to ground) PLL capacitor as close to the PLL and ground pins on the chip as possible, and put the series RC part of the loop filter on the other side of the main capacitor. I'll sketch a picture if anyone's interested.

This is what I do for a living. Designing a PLL to drive a FM radio transmitter isn't particularly fun; any phase noise or instability arising in the loop filter will be broadcasted and received by listeners. And layout is critical - a frequency synthesizer board might work incredibly well on the bench, but act like an antenna when you put the board in a 40KW FM transmitter. 😀 We spend months designing these things...
 
#35
One difference between the two parts is the filter values have changed. the 8414 uses a 470 ohm and a .068uf caps. I the 8412 uses a 1K and .047uf caps, you may not need to changes these parts. I have change the 8412 in my DAC to and 8414 work fine. WWW.MOUSER.COM has the SOIC headers. 🙂

Yea I'm using NPO ceramic caps in my filter.
 
#36
Resurrecting this old thread.

Does anybody know if the wildmonkeysect CS8412 tweak on the loop filter is also applicable on the CS8411?
Since the 2 components are of the same gen and are on the same crystal datasheet, I am guessing yes... but obviously I am seeking for some confirmation 🙂

I was also trying to understand how the wildmonkeysect tweak values were found? What are he equations and what does it do?
 
#37
From the point of view of data recovery and PLL operation, the CS8412 and CS8411 are virtually identical. The two chips have identical requirements from the loop filter.

They differ in the way that channel status and auxilliary data are presented to the outside world.
 
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