MAX1044 Failure?

[armdnrdy]

A solution should solve a problem. Maybe you do have a ripple problem with the datasheet circuit? In my circuits - and I seem to prefer excessive gain applications - there was never a discernible problem with the charge pump ripple.
Then, how much capacitance should be used? 100u? 1000u? 10000u? The ripple is even lower if one adds an inductance to the circuit. Where should one stop? Trying to improve something without clear goals it's not a sane/cost-effective aproach. It's this approach that leads audiophyles to mass insane amount of capacitance in their circuits.

As they say, "better is the enemy of good".

To answer a few of your questions and comment on your statements,

"A solution should solve a problem" I agree but......there's also the element of being proactive in your designs.
The circuits that I build are usually larger in nature, originally designed incorporating center tapped transformers for a bi polar supply.
They are not "excessive gain" fuzz or overdrive circuits which would not be as susceptible to unwanted PS noise.

I usually build flangers and phasers.....some that were originally rack mount units.
When scaling these circuits down to a more "user friendly" stomp box size, one of the first things to go is the transformer.

This has led me to explore several options. I am by no means an expert but I have researched and physically tested various charge pumps, DC-DC converters, (even the antiquated MC34063) and non center tapped AC wall adapter solutions.

One day it occurred to me that I was testing these circuits with no load and that to get accurate results I would have to test under different load conditions. So I built a constant current load or "dummy load".






how much capacitance should be used? 100u? 1000u? 10000u?
I would say that it varies greatly with the circuit and the results you want to achieve. Using a charge pump circuit in a EHX Attack decay build, I used the original circuit's 220µf caps.

Trying to improve something without clear goals it's not a sane/cost-effective aproach.
It may not seem clear but.......I do have clear goals.......to incorporate a smaller, alternative power supply that doesn't introduce any audible artifacts into the circuit's power supply. Simple! 

I don't really worry about this approach being "cost effective" for I do not build for profit.....and the cost difference between a 10µf cap and a 220µf cap is very miniscule.

[ggedamed]

On this discussion... my OPINION would be.

Use small transfer caps (10uf) as there has to be some limit as to how much power can be transferred depending on frequency.  Then, if you are concerned with ripple/noise, ADD addtional filter caps and circuitry as needed.  That's what I am doing.

My .02

MC

+1 (or should I say +.02  )

A solution should solve a problem. Maybe you do have a ripple problem with the datasheet circuit? In my circuits - and I seem to prefer excessive gain applications - there was never a discernible problem with the charge pump ripple.
Then, how much capacitance should be used? 100u? 1000u? 10000u? The ripple is even lower if one adds an inductance to the circuit. Where should one stop? Trying to improve something without clear goals it's not a sane/cost-effective aproach. It's this approach that leads audiophyles to mass insane amount of capacitance in their circuits.

As they say, "better is the enemy of good".

To answer a few of your questions and comment on your statements,

"A solution should solve a problem" I agree but......there's also the element of being proactive in your designs.
The circuits that I build are usually larger in nature, originally designed incorporating center tapped transformers for a bi polar supply.
They are not "excessive gain" fuzz or overdrive circuits which would not be as susceptible to unwanted PS noise.

I usually build flangers and phasers.....some that were originally rack mount units.
When scaling these circuits down to a more "user friendly" stomp box size, one of the first things to go is the transformer.

This has led me to explore several options. I am by no means an expert but I have researched and physically tested various charge pumps, DC-DC converters, (even the antiquated MC34063) and non center tapped AC wall adapter solutions.

One day it occurred to me that I was testing these circuits with no load and that to get accurate results I would have to test under different load conditions. So I built a constant current load or "dummy load".






how much capacitance should be used? 100u? 1000u? 10000u?
I would say that it varies greatly with the circuit and the results you want to achieve. Using a charge pump circuit in a EHX Attack decay build, I used the original circuit's 220µf caps.

Trying to improve something without clear goals it's not a sane/cost-effective aproach.
It may not seem clear but.......I do have clear goals.......to incorporate a smaller, alternative power supply that doesn't introduce any audible artifacts into the circuit's power supply. Simple!  

I don't really worry about this approach being "cost effective" for I do not build for profit.....and the cost difference between a 10µf cap and a 220µf cap is very miniscule.

Hmm, all nice and dandy, but I still don't understand if your tests showed any audible artifacts.
Why do you think fuzzes and distortions are not as susceptible to PSU problems as a flanger? This goes against everything I experienced and read.
Being proactive and not worrying about cost is audiophyle argumentation. Sorry, I don't go there.
BTW, here's a quote from the same link you sent me to read:

To reduce ripple, you must isolate ripple sources from the rest of the circuit. For best conversion efficiency in the charge pump, you should also minimize ESR and ensure that the input-, output-, and pump-capacitor values are as close as possible to those recommended in the data sheet.

OFF-TOPIC: why do you need a constant current load for testing PSUs?

[armdnrdy]

If you are going to pull something out of a data sheet to use to try to debunk someone's premise......please do not edit it.

BTW, here's a quote from the same link you sent me to read:

To reduce ripple, you must isolate ripple sources from the rest of the circuit. For best conversion efficiency in the charge pump, you should also minimize ESR and ensure that the input-, output-, and pump-capacitor values are as close as possible to those recommended in the data sheet.

The section you pulled out of the data sheet is referring to and directly below this image:



By any chance did you notice the 100µf caps on the input, output, and for the "flying" cap?

Here's the data sheet for the LT1054:
http://cds.linear.com/docs/en/datasheet/1054lfg.pdf

I believe that you will find a few more 100µf caps under "typical applications" pg.10-12

I'm finished debating with someone who just seems to want to argue well known facts, who questions one's research/testing, and who offers no real examples.....save for his opinion!

I originally posted on this thread to offer help to the original poster, which I believe I accomplished. I did not post to become engaged in an argument.

This is my last post on this thread.

[ggedamed]

If you are going to pull something out of a data sheet to use to try to debunk someone's premise......please do not edit it.

BTW, here's a quote from the same link you sent me to read:

To reduce ripple, you must isolate ripple sources from the rest of the circuit. For best conversion efficiency in the charge pump, you should also minimize ESR and ensure that the input-, output-, and pump-capacitor values are as close as possible to those recommended in the data sheet.

The section you pulled out of the data sheet is referring to and directly below this image:



By any chance did you notice the 100µf caps on the input, output, and for the "flying" cap?

Here's the data sheet for the LT1054:
http://cds.linear.com/docs/en/datasheet/1054lfg.pdf

I believe that you will find a few more 100µf caps under "typical applications" pg.10-12

I'm finished debating with someone who just seems to want to argue well known facts, who questions one's research/testing, and who offers no real examples.....save for his opinion!

I originally posted on this thread to offer help to the original poster, which I believe I accomplished. I did not post to become engaged in an argument.

This is my last post on this thread.

I don't have any problem with replying.
The quote was from your link and I gave the link again in my post, so where's the editing? On the image you're referring says MAX665, so it wasn't connected to the topic in my view. Our controversy's topic - let me remind you - is if one should use the datasheet values or not. If the datasheet circuits contain large capacitors, it's OK with me. So if some LT1054 datasheet circuits have large capacitors in them, that's the way to use them. No argument here.

Everybody is posting to help or so I hope.
For me, "well known facts" are in the same league with "being proactive", if they're not backed up by some hard data.
BTW, I should point that in my language "argument" means only "reason", it doesn't have the "quarrel" connotation. I intended to use it only with the "reason" meaning and I apologize if I misused it.

[chromesphere]

Ahem...

I use the TC1044scpa ('low noise') and I find its stable, cheaper then the lt1054, and doesn't explode in inverter circuits like the max.  I have killed too many max's to ever buy one again, I just cant do it.  They just cant handle the task at hand (supply -9v to the circuit).  I've found from experience that the TC1044 is quieter then the LT1054 but I have never tried adding that capacitor from pin 2 to 7 on the LT however.

Hope that helps!
Paul