C0G caps have no significant capacitance change with voltage?

[Faringdon]

Hi,
https://www.murata.com/en-eu/support/faqs/capacitor/ceramiccapacitor/char/0005

...but please may i confirm that C0G has no appreciable capacitance change with voltage.
We know X7R changes cap'ance majorly with voltage...but C0G is just like film or 'lytics w.r.t. voltage change? (dc bias)

[tggzzz]

Oh. Good. Grief.

Why do you think people here can offer a more authoritative statement than the manufacturer?

Or do you just want to chat and form a mutual support/appreciation society?

[coppice]

Oh. Good. Grief.

Why do you think people here can offer a more authoritative statement than the manufacturer?

Or do you just want to chat and form a mutual support/appreciation society?

I agree. Manufacturers are ALWAYS totally open and honest about all the negative points of their products, and can be trusted at all times to clearly point them out in their literature.

[tggzzz]

Oh. Good. Grief.

Why do you think people here can offer a more authoritative statement than the manufacturer?

Or do you just want to chat and form a mutual support/appreciation society?

I agree. Manufacturers are ALWAYS totally open and honest about all the negative points of their products, and can be trusted at all times to clearly point them out in their literature.

And random people commenting on forums are ALWAYS an accurate source of detailed specifications suitable for  professionals designing commercial products.

Treez faringdon is a professional designing commercial producrs, isn't he?

[coppice]

Oh. Good. Grief.

Why do you think people here can offer a more authoritative statement than the manufacturer?

Or do you just want to chat and form a mutual support/appreciation society?

I agree. Manufacturers are ALWAYS totally open and honest about all the negative points of their products, and can be trusted at all times to clearly point them out in their literature.

And random people commenting on forums are ALWAYS an accurate source of detailed specifications suitable for  professionals designing commercial products.

You can't trust them, but they will often point out things you should look into deeper in the documentation and set you on the path to greater understanding. You never know. If enough people join in you might even flush out a genuine expert.... assuming you can distinguish genuine from fake.

I suspect you may have let the nature of the OP set you on a path of bad argument.

[tggzzz]

Oh. Good. Grief.

Why do you think people here can offer a more authoritative statement than the manufacturer?

Or do you just want to chat and form a mutual support/appreciation society?

I agree. Manufacturers are ALWAYS totally open and honest about all the negative points of their products, and can be trusted at all times to clearly point them out in their literature.

And random people commenting on forums are ALWAYS an accurate source of detailed specifications suitable for  professionals designing commercial products.

You can't trust them, but they will often point out things you should look into deeper in the documentation and set you on the path to greater understanding. You never know. If enough people join in you might even flush out a genuine expert.... assuming you can distinguish genuine from fake.

I suspect you may have let the nature of the OP set you on a path of bad argument.

That point doesn't stand up in the context of the original post, viz

Hi,
https://www.murata.com/en-eu/support/faqs/capacitor/ceramiccapacitor/char/0005

...but please may i confirm that C0G has no appreciable capacitance change with voltage.
We know X7R changes cap'ance majorly with voltage...but C0G is just like film or 'lytics w.r.t. voltage change? (dc bias)

[Zero999]

C0G/NP0 capacitors don't have a strong voltage vs capacitance characteristic. I suppose fakes exist, which is the case for every other kind of component.

https://www.allaboutcircuits.com/technical-articles/x7r-x5r-c0g...-a-concise-guide-to-ceramic-capacitor-types/

[Terry Bites]

Oh my days.....!

[Nominal Animal]

Hey, the question does have merit.  NP0=C0G dielectrics are defined by having capacitance basically independent of temperature (temperature coefficient α within ±0.00003 per degree Kelvin or Celsius), and no aging effects, but the voltage-capacitance relationship is somewhat separate.

As I discovered different types of dielectrics and their properties, I encountered the Temp and voltage variation of ceramic caps article at EDN (and a variant at analog.com).
That shows that even for X7R and X5R dielectrics, the dependency varies depending on the voltage rating, but also on the capacitor physical size.  The information was taken from public information provided by two different reputable manufacturers (Murata and TDK), so it is credible.

I did not find any curves, but all capacitor manufacturers do claim that C0G (aka NP0) capacitors have basically no voltage dependency in their capacitance, within the maximum voltage the capacitor is rated for.

The underlying question, then, is whether this is true, or if it is a common misconception stemming from their neglible temperature coefficient.

As I am only a hobbyist in electronics, and a scientist, to me an experiment with a few different C0G caps would nicely resolve the question: measure the capacitance of the caps at different bias voltages.  (Can one DC-bias only one leg of a Wien bridge?)

Any suggestions for such a circuit, measuring the capacitance of a DC-biased capacitor?

[mawyatt]

Hey, the question does have merit.  NP0=C0G dielectrics are defined by having capacitance basically independent of temperature (temperature coefficient α within ±0.00003 per degree Kelvin or Celsius), and no aging effects, but the voltage-capacitance relationship is somewhat separate.

As I discovered different types of dielectrics and their properties, I encountered the Temp and voltage variation of ceramic caps article at EDN (and a variant at analog.com).
That shows that even for X7R and X5R dielectrics, the dependency varies depending on the voltage rating, but also on the capacitor physical size.  The information was taken from public information provided by two different reputable manufacturers (Murata and TDK), so it is credible.

I did not find any curves, but all capacitor manufacturers do claim that C0G (aka NP0) capacitors have basically no voltage dependency in their capacitance, within the maximum voltage the capacitor is rated for.

The underlying question, then, is whether this is true, or if it is a common misconception stemming from their neglible temperature coefficient.

As I am only a hobbyist in electronics, and a scientist, to me an experiment with a few different C0G caps would nicely resolve the question: measure the capacitance of the caps at different bias voltages.  (Can one DC-bias only one leg of a Wien bridge?)

Any suggestions for such a circuit, measuring the capacitance of a DC-biased capacitor?

We did develop a DC Bias adapter for our bench LCR meters for this reason (one of which), to evaluate the various aspects of ceramic capacitors DC voltage bias effects. This confirmed the high voltage bias variability of X7R and X5R dielectrics which we already knew, but also provided a means to evaluate some new "questionable" sources for various ceramic capacitors. The NP0/C0G ceramics we've evaluate from Venkel are stable with voltage, temperature and time as we've learned.

https://www.eevblog.com/forum/projects/bias-network-for-lcr-meter/
https://www.eevblog.com/forum/testgear/lcr-meter-plot-software/msg4810088/#msg4810088

We've learned over the many years to not trust just every OEM for, components, test equipment and so on, and some newer ones without a history with us needed to be evaluated. This is especially true today with the counterfeit components lurking from the questionable OEMs and distributors. Over 50 years ago we suffered from a local main distributor of passive components, they were eventually caught and prosecuted for selling counterfeit components. Our case involved counterfeit 0.1% RN55 and 60 "E" type resistors, they were hand selected from remarked 1% RN55 and 60 "C" and "D" components. These were utilized in various critical measurement equipment we developed and sold, and we had no way of knowing if/what product these counterfeit components ended up in, so we had to recall various products, embarrassing indeed 

Ever since we've been somewhat cautious about "unknown" to us sources, and try to evaluate before blindly using such in valued applications/products/recommendations.

Best,

[T3sl4co1l]

FWIW, my tests have shown very little distortion at 200V AC applied to 630V C0G chips.  Gapped ferrite is certainly more.

Tim

[coppice]

Ever since we've been somewhat cautious about "unknown" to us sources, and try to evaluate before blindly using such in valued applications/products/recommendations.

Capacitors and dielectric materials are a minefield when you care about details of capacitive performance. For example kapton is often used as a dielectric for capacitive touch pads. Try various sources of apparently similar kapton tapes. A quick touch is never a problem. However, with some if you hold a finger on the pad for a minute or two, and then lift your finger, the capacitance reading goes straight back to its pre-touched value. Try another similar material and polarisation effects mean the capacitance drops to a substantially different value, and can take a minute or two to drift back to its pre-touched value. That's a lot of fun when a new production batch suddenly starts failing because the software calibration process can't cope with this.

[T3sl4co1l]

Ever since we've been somewhat cautious about "unknown" to us sources, and try to evaluate before blindly using such in valued applications/products/recommendations.

Capacitors and dielectric materials are a minefield when you care about details of capacitive performance. For example kapton is often used as a dielectric for capacitive touch pads. Try various sources of apparently similar kapton tapes. A quick touch is never a problem. However, with some if you hold a finger on the pad for a minute or two, and then lift your finger, the capacitance reading goes straight back to its pre-touched value. Try another similar material and polarisation effects mean the capacitance drops to a substantially different value, and can take a minute or two to drift back to its pre-touched value. That's a lot of fun when a new production batch suddenly starts failing because the software calibration process can't cope with this.

Not to mention humidity from the finger; polyimide (Kapton(R) is the brand name) is an effective humidity sensor.

Tim

[mawyatt]

Should mention that some C0G/N0P ceramic caps are so good, that some high end DMMs use them as the main integration capacitor. That should hint at just how good they can be!! I'm sure there are some "fake" C0G/N0P caps around, but those should be easy to find with a simple bias voltage test. Maybe some questionable OEM brands, altho the Venkel C0Gs we have and use as internal "reference" devices to check and confirm proper operation of our LCR Meters, they are that stable.

Best,

[coppice]

Ever since we've been somewhat cautious about "unknown" to us sources, and try to evaluate before blindly using such in valued applications/products/recommendations.

Capacitors and dielectric materials are a minefield when you care about details of capacitive performance. For example kapton is often used as a dielectric for capacitive touch pads. Try various sources of apparently similar kapton tapes. A quick touch is never a problem. However, with some if you hold a finger on the pad for a minute or two, and then lift your finger, the capacitance reading goes straight back to its pre-touched value. Try another similar material and polarisation effects mean the capacitance drops to a substantially different value, and can take a minute or two to drift back to its pre-touched value. That's a lot of fun when a new production batch suddenly starts failing because the software calibration process can't cope with this.

Not to mention humidity from the finger; polyimide (Kapton(R) is the brand name) is an effective humidity sensor.

Tim

Its rare in a touch setup that moisture from the finger could reach the kapton. You could consider warming by the finger too. That doesn't seem to have much effect. As far as I know its basically a polarisation effect. It comes up in dielectric issues all over the place.

[Nominal Animal]

Polyimide is also triboelectric, making it a particularly odd choice for a capacitive touch dielectric material.

[coppice]

Polyimide is also triboelectric, making it a particularly odd choice for a capacitive touch dielectric material.

That makes it an odd choice for a lot of places its widely used, like flexible PCBs. Its really the flexible PCB use of kapton that leads it to be used for touch applications.

[dmills]

The only real trap with MLCC C0G is dielectric absorption, which can sometimes be a bit higher then good film part in PP or PPS, but 'higher' is not the same as particularly bad, and they are just fine in most applications for such things.

Not sure I would use them in an application that wanted a self healing part, they are obviously not designed or specified for that.

For general HF coupling, filtering, timing they do just fine. Integrators, well, do sums based on application to decide if you can live with the dielectric absorption effects, you usually can but you need to check.

Pick a vendor with good data and ideally a decent reputation, I tend to default to Murata but there are plenty of others, the good data being the selling point, and look for the long form data not the one page cut sheet, then read the docs and maybe do some experiments to see how things really shake out. 

[T3sl4co1l]

Not sure I would use them in an application that wanted a self healing part, they are obviously not designed or specified for that.

That said, there are SMT Y caps:
https://www.digikey.com/short/mtm37z0n
Use at your own risk, I suppose.

Not to doubt their value, just that the footprint area is comparable to a THT and it's probably a somewhat specialized application that 1. has low enough vibration to accommodate ceramics reliably and 2. is specialized enough to swallow the cost of these things.

Tim

[mawyatt]

Polyimide is also triboelectric, making it a particularly odd choice for a capacitive touch dielectric material.

That makes it an odd choice for a lot of places its widely used, like flexible PCBs. Its really the flexible PCB use of kapton that leads it to be used for touch applications.

And on some semiconductors as passivation.

Best,

[gnuarm]

Oh. Good. Grief.

Why do you think people here can offer a more authoritative statement than the manufacturer?

Or do you just want to chat and form a mutual support/appreciation society?

I agree. Manufacturers are ALWAYS totally open and honest about all the negative points of their products, and can be trusted at all times to clearly point them out in their literature.

I can't tell if you are being sarcastic or not.  Capacitor makers, especially, do not publish every detail you would want to know.  The link provided by the OP talks about voltage variation of capacitance in the "high" dielectric caps, but not in the temperature compensated caps.  Or did I miss that?

[gnuarm]

Oh. Good. Grief.

Why do you think people here can offer a more authoritative statement than the manufacturer?

Or do you just want to chat and form a mutual support/appreciation society?

I agree. Manufacturers are ALWAYS totally open and honest about all the negative points of their products, and can be trusted at all times to clearly point them out in their literature.

And random people commenting on forums are ALWAYS an accurate source of detailed specifications suitable for  professionals designing commercial products.

Treez faringdon is a professional designing commercial producrs, isn't he?

Then there are the people who offer nothing in answering the question, but rag about the question being stupid.  Why don't you let others reply? 

[T3sl4co1l]

Oh. Good. Grief.

Why do you think people here can offer a more authoritative statement than the manufacturer?

Or do you just want to chat and form a mutual support/appreciation society?

I agree. Manufacturers are ALWAYS totally open and honest about all the negative points of their products, and can be trusted at all times to clearly point them out in their literature.

I can't tell if you are being sarcastic or not.  Capacitor makers, especially, do not publish every detail you would want to know.  The link provided by the OP talks about voltage variation of capacitance in the "high" dielectric caps, but not in the temperature compensated caps.  Or did I miss that?

Is coppice ever not sarcastic?

Tim

[DavidAlfa]

They're very stable in all circunstamces but also have low capacitances, so rarely useful except for tuned circuits.

[gnuarm]

They're very stable in all circunstamces but also have low capacitances, so rarely useful except for tuned circuits.

Not really accurate.  Tuned circuits are not the only type where C0G caps are useful.  And "low" is a subjective term.  It means nothing really.  I know people who regularly use 1 pF caps.  Yeah, really.