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Weight of a 1210 SMT capacitor?

Started by Jeff Liebermann March 24, 2014
Google search has finally failed me.  I can't find the weight of a
1210 SMT capacitor so that I can guestimate its final temperature from
the dissipation and the specific heat.  All I can find is either zero
grams or weights that include the packaging material.

Specifically, I need the approximate weight of a AVX 1210 SQ CB series
cap:
<http://www.avx.com/docs/Catalogs/sqca-sqcb.pdf>
Yes, I know it varies with part value.  I just need a 2 decimal place
ballpark value for the weight.  I would weigh some caps myself except
that my scale and SMT cap stash are not easily available.

-- 
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558
Jeff Liebermann <jeffl@cruzio.com> wrote:
> I can't find the weight of a 1210 SMT capacitor so that I can > guestimate its final temperature from the dissipation and the > specific heat.
Assume it's all lead, assume it's all hydrogen, see if you like either result?
> Yes, I know it varies with part value. I just need a 2 decimal place > ballpark value for the weight.
I don't know if these are close enough to what you have or not, but TDK says * the following for their MLCC: Case Milligrams 1005 1.25 1608 5.12 2012 7.50 C0G, 10.63 or 15.63 X7R (depends on thickness) * http://www.digikey.com/Web%20Export/Supplier%20Content/TDK_445/PDF/TDK_env_faq.pdf?redirected=1 Matt Roberds
On 3/24/2014 9:52 PM, mroberds@att.net wrote:
> Jeff Liebermann <jeffl@cruzio.com> wrote: >> I can't find the weight of a 1210 SMT capacitor so that I can >> guestimate its final temperature from the dissipation and the >> specific heat. > > Assume it's all lead, assume it's all hydrogen, see if you like either > result? > >> Yes, I know it varies with part value. I just need a 2 decimal place >> ballpark value for the weight. > > I don't know if these are close enough to what you have or not, but TDK > says * the following for their MLCC: > > Case Milligrams > 1005 1.25 > 1608 5.12 > 2012 7.50 C0G, 10.63 or 15.63 X7R (depends on thickness) > > * http://www.digikey.com/Web%20Export/Supplier%20Content/TDK_445/PDF/TDK_env_faq.pdf?redirected=1 > > Matt Roberds >
I probably won't be much help but I weighed 3-Vishay Multilayer ceramic 1206 caps. MLCC (VJ1206Y152KXAMC) 1500pf 3 = 0.071 grams So; 1 = 0.0237 grams Mikek
On Mon, 24 Mar 2014 19:18:31 -0700, Jeff Liebermann <jeffl@cruzio.com> wrote:

>Google search has finally failed me. I can't find the weight of a >1210 SMT capacitor so that I can guestimate its final temperature from >the dissipation and the specific heat. All I can find is either zero >grams or weights that include the packaging material. > >Specifically, I need the approximate weight of a AVX 1210 SQ CB series >cap: ><http://www.avx.com/docs/Catalogs/sqca-sqcb.pdf> >Yes, I know it varies with part value. I just need a 2 decimal place >ballpark value for the weight. I would weigh some caps myself except >that my scale and SMT cap stash are not easily available.
I tested a 7.5 ohm 1206 resistor. It exploded in 1 millisecond at 65 watts. Here are some tests with a 1206 platinum RTD: https://dl.dropboxusercontent.com/u/53724080/Thermal/RTD_in_air.JPG https://dl.dropboxusercontent.com/u/53724080/Thermal/RTD_lotsa_copper.JPG https://dl.dropboxusercontent.com/u/53724080/Thermal/RTD_on_board.JPG It's probably in the ballpark of the thermal mass of a 1206 cap, maybe less if the cap is thicker. You can estimate theta and the thermal tau from those scope shots. The theta and tau depend mightily on what it's soldered to. This must be RF if you care about a cap getting hot. And pulsed, if you care about the thermal mass. -- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation
On Mon, 24 Mar 2014 20:17:24 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

>On Mon, 24 Mar 2014 19:18:31 -0700, Jeff Liebermann <jeffl@cruzio.com> wrote: > >>Google search has finally failed me. I can't find the weight of a >>1210 SMT capacitor so that I can guestimate its final temperature from >>the dissipation and the specific heat. All I can find is either zero >>grams or weights that include the packaging material. >> >>Specifically, I need the approximate weight of a AVX 1210 SQ CB series >>cap: >><http://www.avx.com/docs/Catalogs/sqca-sqcb.pdf> >>Yes, I know it varies with part value. I just need a 2 decimal place >>ballpark value for the weight. I would weigh some caps myself except >>that my scale and SMT cap stash are not easily available.
>I tested a 7.5 ohm 1206 resistor. It exploded in 1 millisecond at 65 watts.
These caps will be dissipating about 0.6 watts.
>This must be RF if you care about a cap getting hot. And pulsed, if you care >about the thermal mass.
Thanks much. Yes, it's RF. Output low pass filter from a 300 watt RF power amplifier. That's about 2.5A rms output current into 50 ohms. The existing 20 year old design is both labor and component cost intensive. Management believes they can sell more boxes if I remove or downgrade such frills as cooling fans, shielding, 2 oz copper PCB, somewhat exotic magnetics, silver-mica caps, layout the PCB for pick-n-plop, etc... without also downgrading the specs, of course. Converting quality into junk is my specialty, so I'm doing the initial proposal (due last Friday, of course). The existing radial lead silver mica caps work just fine, with an ESR of about 0.01 ohms at about 10 MHz. Very little temperature rise. Usually, there are two or more caps in parallel to divide the RF current. However, in order to use cheaper ceramic caps, the ESR will be about 10 times higher. The 10x increase in dissipation, combined with a reduction in physical size makes me worry. I don't have time for a bench test, so I'm doing a back of the envelope calculation to see if I'm going to get a working filter, a fire, or an explosion. I'll assume 0.01 grams for the weight of a "typical" 1210, 0.6 watts for 60 seconds (36 Joules), and an adiabatic system, which means I can use a linear approximation. The specific heat of Barium Titanate is about 0.5 J/gK. <http://ewww.theeestory.com/files/12218178.pdf> 0.5 = (watts * seconds) / (grams * Kelvin) 0.5 = (0.6 * 60) / (0.01 * K ) K = (0.6 * 60) / 0.01 * 0.5) K = 7200 K temp rise per minute. Nice bomb which methinks approximates what you obtained with the resistor. I'll add the PCB and solder blob heat sinking (later) and see if the results are more reasonable. I do have an expensive way out. Mica SMT caps such as: <http://www.cde.com/catalogs/MC.pdf> <http://www.cde.com/catalogs/MCM-MIN.pdf> At least they have higher than 500v ratings as I haven't calculated if 500v caps are sufficient. Oh-oh. 300 watts into 50 ohms is about 490 volts peak. Looks like I'll be putting some ceramic caps in series. SPICE simulation if there's time. I think I know what inspired this exercise: <http://www.ebay.com/itm/251465983220> This is the back of the board: <http://i.ebayimg.com/00/s/MTIyMlgxNjAw/z/ffsAAOxy63FS4NHQ/$_57.JPG> Ceramic caps everywhere at 1KW power level. Hmmmm... Yet another all nighter coming. I'm getting too old for this... -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
On Mon, 24 Mar 2014 19:18:31 -0700, the renowned Jeff Liebermann
<jeffl@cruzio.com> wrote:

>Google search has finally failed me. I can't find the weight of a >1210 SMT capacitor so that I can guestimate its final temperature from >the dissipation and the specific heat. All I can find is either zero >grams or weights that include the packaging material. > >Specifically, I need the approximate weight of a AVX 1210 SQ CB series >cap: ><http://www.avx.com/docs/Catalogs/sqca-sqcb.pdf> >Yes, I know it varies with part value. I just need a 2 decimal place >ballpark value for the weight. I would weigh some caps myself except >that my scale and SMT cap stash are not easily available.
If you ignore the metalization and end caps and assume it's all a fairly dense ceramic, say Alumina at ~4g/cm^3... http://global.kyocera.com/prdct/fc/list/tokusei/hiju/index.html Dimensions are 2.79 x 2.79 x 0.76mm = 5.91mm^3 for the 'B' case size. At 4g/cm^3, that's ~24mg. By way of comparison, the density of the TDK caps that Matt pointed to (COG 3216) is 5g/cm^3, so it checks out reasonably well. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
On Mon, 24 Mar 2014 20:17:24 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

>I tested a 7.5 ohm 1206 resistor. It exploded in 1 millisecond at 65 watts.
(...)
>It's probably in the ballpark of the thermal mass of a 1206 cap, maybe less if >the cap is thicker. You can estimate theta and the thermal tau from those scope >shots. The theta and tau depend mightily on what it's soldered to.
Good idea. I'm dealing with 0.6 watts and 0.1 ohms. So, if 65 watts blows the resistor in 0.001 sec, then 0.6 watts will blow it in 0.1 sec. Since the resistance is 75 times lower, the power dissipated will also be 75 times lower. That yields 7.5 seconds, which I think is probably high because I'm too lazy to convert the temperature range to Kelvin. The volume of the 1210 package is about 50% more than the 1206, yielding 11 seconds to explosion. This is not looking very good for using SMT caps so far. If I was going to calculate more accurate times and temperatures, I would use the slope of your resistor curves to estimate the effects of radiation, PCB conduction, and air convection. However, I just want an order of magnitude ballpark number at this point. Besides, I'm now doing battle with SketchUp rehashing the package and giving the re-design review committee something they can understand and throw rocks at. Anyway, I don't think it's going to matter. The high voltages and moderate heat dissipations involved will probably require at least 6 SMT caps to replace two existing radial silver mica caps. Even with parts prep and pick and plop assembly savings, the estimated costs are about the same. In other words, there's no cost savings in using SMT caps. I haven't priced out the mica SMT caps, which offer some cost benefits. Midnight, and no end in sight... -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Le Mon, 24 Mar 2014 21:50:11 -0700, Jeff Liebermann a &eacute;crit:

> On Mon, 24 Mar 2014 20:17:24 -0700, John Larkin > <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote: > >>On Mon, 24 Mar 2014 19:18:31 -0700, Jeff Liebermann <jeffl@cruzio.com> >>wrote: >> >>>Google search has finally failed me. I can't find the weight of a 1210 >>>SMT capacitor so that I can guestimate its final temperature from the >>>dissipation and the specific heat. All I can find is either zero grams >>>or weights that include the packaging material. >>> >>>Specifically, I need the approximate weight of a AVX 1210 SQ CB series >>>cap: >>><http://www.avx.com/docs/Catalogs/sqca-sqcb.pdf> >>>Yes, I know it varies with part value. I just need a 2 decimal place >>>ballpark value for the weight. I would weigh some caps myself except >>>that my scale and SMT cap stash are not easily available. > >>I tested a 7.5 ohm 1206 resistor. It exploded in 1 millisecond at 65 >>watts. > > These caps will be dissipating about 0.6 watts. > >>This must be RF if you care about a cap getting hot. And pulsed, if you >>care about the thermal mass. > > Thanks much. > > Yes, it's RF. Output low pass filter from a 300 watt RF power > amplifier. That's about 2.5A rms output current into 50 ohms. The > existing 20 year old design is both labor and component cost intensive. > Management believes they can sell more boxes if I remove or downgrade > such frills as cooling fans, shielding, 2 oz copper PCB, somewhat exotic > magnetics, silver-mica caps, layout the PCB for pick-n-plop, etc... > without also downgrading the specs, of course. Converting quality into > junk is my specialty, so I'm doing the initial proposal (due last > Friday, of course). > > The existing radial lead silver mica caps work just fine, with an ESR of > about 0.01 ohms at about 10 MHz. Very little temperature rise. Usually, > there are two or more caps in parallel to divide the RF current. > However, in order to use cheaper ceramic caps, the ESR will be about 10 > times higher. The 10x increase in dissipation, combined with a > reduction in physical size makes me worry. I don't have time for a > bench test, so I'm doing a back of the envelope calculation to see if > I'm going to get a working filter, a fire, or an explosion. > > I'll assume 0.01 grams for the weight of a "typical" 1210, 0.6 watts for > 60 seconds (36 Joules), and an adiabatic system, which means I can use a > linear approximation. The specific heat of Barium Titanate is about 0.5 > J/gK. > <http://ewww.theeestory.com/files/12218178.pdf> > 0.5 = (watts * seconds) / (grams * Kelvin) > 0.5 = (0.6 * 60) / (0.01 * K ) > K = (0.6 * 60) / 0.01 * 0.5) > K = 7200 K temp rise per minute. > Nice bomb which methinks approximates what you obtained with the > resistor. I'll add the PCB and solder blob heat sinking (later) and see > if the results are more reasonable. > > I do have an expensive way out. Mica SMT caps such as: > <http://www.cde.com/catalogs/MC.pdf> > <http://www.cde.com/catalogs/MCM-MIN.pdf> > At least they have higher than 500v ratings as I haven't calculated if > 500v caps are sufficient. Oh-oh. 300 watts into 50 ohms is about 490 > volts peak. Looks like I'll be putting some ceramic caps in series. > SPICE simulation if there's time. > > I think I know what inspired this exercise: > <http://www.ebay.com/itm/251465983220> > This is the back of the board: > <http://i.ebayimg.com/00/s/MTIyMlgxNjAw/z/ffsAAOxy63FS4NHQ/$_57.JPG> > Ceramic caps everywhere at 1KW power level. Hmmmm... > > Yet another all nighter coming. I'm getting too old for this...
Did you look at ATC caps? www.atceramics.com -- Thanks, Fred.
On Monday, March 24, 2014 10:18:31 PM UTC-4, Jeff Liebermann wrote:
> Google search has finally failed me. I can't find the weight of a > > 1210 SMT capacitor so that I can guestimate its final temperature from > > the dissipation and the specific heat. All I can find is either zero > > grams or weights that include the packaging material.
Hey you're in luck... you don't have to weight it (and then figure out what it's made of.) The heat capacity of everything* is about 3.0 J/(K * cm^3) so just determine the volume. George H. * ok I have numbers for a few materials, but I couldn't find them in my note book. (All at ~300K) Cu = 3.4 Al = 2.4 Fe = 3.5 Al2O3 = 3.0
> > > > Specifically, I need the approximate weight of a AVX 1210 SQ CB series > > cap: > > <http://www.avx.com/docs/Catalogs/sqca-sqcb.pdf> > > Yes, I know it varies with part value. I just need a 2 decimal place > > ballpark value for the weight. I would weigh some caps myself except > > that my scale and SMT cap stash are not easily available. > > > > -- > > Jeff Liebermann jeffl@cruzio.com > > 150 Felker St #D http://www.LearnByDestroying.com > > Santa Cruz CA 95060 http://802.11junk.com > > Skype: JeffLiebermann AE6KS 831-336-2558
On Tuesday, March 25, 2014 1:07:21 AM UTC-4, Spehro Pefhany wrote:
> On Mon, 24 Mar 2014 19:18:31 -0700, the renowned Jeff Liebermann > > <jeffl@cruzio.com> wrote: > > > > >Google search has finally failed me. I can't find the weight of a > > >1210 SMT capacitor so that I can guestimate its final temperature from > > >the dissipation and the specific heat. All I can find is either zero > > >grams or weights that include the packaging material. > > > > > >Specifically, I need the approximate weight of a AVX 1210 SQ CB series > > >cap: > > ><http://www.avx.com/docs/Catalogs/sqca-sqcb.pdf> > > >Yes, I know it varies with part value. I just need a 2 decimal place > > >ballpark value for the weight. I would weigh some caps myself except > > >that my scale and SMT cap stash are not easily available. > > > > If you ignore the metalization and end caps and assume it's all a > > fairly dense ceramic, say Alumina at ~4g/cm^3... > > > > http://global.kyocera.com/prdct/fc/list/tokusei/hiju/index.html > > > > Dimensions are 2.79 x 2.79 x 0.76mm = 5.91mm^3 for the 'B' case size. >
There ya go.. so 3.0 (J/(K*cm^3) *6 mm^3 ~ 18 mJ/K George h.
> > At 4g/cm^3, that's ~24mg. > > > > By way of comparison, the density of the TDK caps that Matt pointed to > > (COG 3216) is 5g/cm^3, so it checks out reasonably well. > > > > > > Best regards, > > Spehro Pefhany > > -- > > "it's the network..." "The Journey is the reward" > > speff@interlog.com Info for manufacturers: http://www.trexon.com > > Embedded software/hardware/analog Info for designers: http://www.speff.com