Capacitors and ESD
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From: Wimpie on 19 Jan 2010 18:11 On 19 ene, 16:31, Wimpie <wimabc...(a)tetech.nl> wrote: > On 19 ene, 00:39, blanko <electro...(a)yahoo.com> wrote: > > > Are capacitors ESD sensitive? Please explain. > > > Ceramtic? > > > Tantalum? > > > I know that some of the ceramic caps that I am working with are rated > > at 25 volts. An ESD zap can be multiples of 1000 V. I believe that > > the capacitors are ESD sensitive because I will exceed the max rated > > voltage. Is this true? > > > Thank you. > > > -E > > Hello, > > Yes ESD can destroy MLCC capacitors, even below the voltage breakdown > limit. Try to locate "DC, AC and Pulse Load > of Multilayer Ceramic Capacitors". This is a former PHILIPS document. > You can probably find it onwww.koaspeer.comalso. There are more > documents around, but this one gives the data in an easy to understand > way. > > If you can't locate it, please contact me. > > Best regards, > > Wim > PA3DJSwww.tetech.nl > without abc your PM will reach me. Addition to text shown above: The link to the document is: http://www.koaspeer.com/pdfs/MLCC.pdf Best regards, Wim PA3DJS www.tetech.nl (Dutch)
From: blanko on 21 Jan 2010 11:19 Wim, I just sat down and read the document: http://www.koaspeer.com/pdfs/MLCC.pdf I was hoping that if ESD was a problem for capacitors that I would be able to clearly understand that indeed there is an ESD issue. From what I have read and digested - it seems that there is not an ESD issue with capacitors. Page 7 starts the section on ESD Pulses. "The immunity of MLCCs to ESD pulses is not well characterized" "When subjected to ESD pulses, low-capacitance MLCC's sometimes exhibited corona effects without internal damage" "All products were resistant to at least 2.5 kV HBM [Human Body Model] and 1kV MM [Machine Model ]pules. 0805 and 1206 products showed the same behaviour." There are two graphs Fig. 12 and Fig. 14 that show the experimental data on ESD immunity. I am not sure how to interpret these graphs. Are the areas that are shaded problem areas? Thanks for any clarification. -H > Addition to text shown above: > > The link to the document is:http://www.koaspeer.com/pdfs/MLCC.pdf > > Best regards, > > Wim > PA3DJSwww.tetech.nl(Dutch)
From: Wimpie on 21 Jan 2010 15:33 On 21 ene, 17:19, blanko <electro...(a)yahoo.com> wrote: > Wim, > > I just sat down and read the document: > > http://www.koaspeer.com/pdfs/MLCC.pdf > > I was hoping that if ESD was a problem for capacitors that I would be > able to clearly understand that indeed there is an ESD issue. From > what I have read and digested - it seems that there is not an ESD > issue with capacitors. Please locate the waveform for the EN 61000-4-2 ESD gun. For the 8 kV pulse, the peak current is 30A. the I^2*t product is significantly higher then the product for the human body model as used in the document. You should carry out I^2*t interpolation between the HBM, "your pulse" and the PHILIPS MM to figure out whether the selected capacitors will survive. > > Page 7 starts the section on ESD Pulses. > > "The immunity of MLCCs to ESD pulses is not well characterized" Therefore they did this investigation. > > "When subjected to ESD pulses, low-capacitance MLCC's sometimes > exhibited corona effects without internal damage" > > "All products were resistant to at least 2.5 kV HBM [Human Body Model] > and 1kV MM [Machine Model ]pules. 0805 and 1206 products showed the > same behaviour." Depending on your environment, EN 61000-4-2 pulses can be up to 8 kV (contact discharge). > > There are two graphs Fig. 12 and Fig. 14 that show the experimental > data on ESD immunity. I am not sure how to interpret these graphs. > Are the areas that are shaded problem areas? Lower edge of shaded area: first capacitor fails, so below the shaded area all survive Higher edge of shaded area: all broken or damaged, so above the shaded area all will be broken. Because of the energy in the MM pulse, the pulse values in figure 14 are far below the voltages in figure 12. [deleted] Best regards, Wim PA3DJS www.tetech.nl
From: JosephKK on 22 Jan 2010 17:56 On Tue, 19 Jan 2010 00:28:46 -0600, "Tim Williams" <tmoranwms(a)charter.net> wrote: >"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message >news:fahal5h0g29cg6dbl69ngejqd9javkiujj(a)4ax.com... >> Ceramic caps are nonlinear enough that you could make a useful >> parametric amplifier from some. >> >> Hmmm, and a fA-sensitive amplifier. > >I recall HP already had made a leakage meter like that, using diode >capacitance instead. > >With pA-sensitive op-amps available these days, there isn't much point in >doing that. Yeah, you said fA, but you'd be taking days to accumulate any >charge to measure it. Unless it was a microscopic hunk, like if you got at >a single cell of FeRAM. Ah, but a monolithic femtoammeter would perform >well, wouldn't it? Still, it would be quite noisy. You might end up with a >better thermometer. > >Tim Comments like this make me appreciate Keithley 619 multimeters better.
From: John Larkin on 22 Jan 2010 19:27
On Fri, 22 Jan 2010 14:56:03 -0800, "JosephKK"<quiettechblue(a)yahoo.com> wrote: >On Tue, 19 Jan 2010 00:28:46 -0600, "Tim Williams" <tmoranwms(a)charter.net> wrote: > >>"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message >>news:fahal5h0g29cg6dbl69ngejqd9javkiujj(a)4ax.com... >>> Ceramic caps are nonlinear enough that you could make a useful >>> parametric amplifier from some. >>> >>> Hmmm, and a fA-sensitive amplifier. >> >>I recall HP already had made a leakage meter like that, using diode >>capacitance instead. >> >>With pA-sensitive op-amps available these days, there isn't much point in >>doing that. Yeah, you said fA, but you'd be taking days to accumulate any >>charge to measure it. Unless it was a microscopic hunk, like if you got at >>a single cell of FeRAM. Ah, but a monolithic femtoammeter would perform >>well, wouldn't it? Still, it would be quite noisy. You might end up with a >>better thermometer. >> >>Tim > >Comments like this make me appreciate Keithley 619 multimeters better. Here's my ebay Keithley 610 measuring a surface-mount 100G resistor, soldered to the Pomona plug. This meter's full-scale ranges go to 1e-14 amps and 1e14 ohms. ftp://jjlarkin.lmi.net/Keithley.JPG And here's my home-made fA parts tester... ftp://jjlarkin.lmi.net/99A260A1.JPG ftp://jjlarkin.lmi.net/99A260A3.JPG ftp://jjlarkin.lmi.net/99S260A.JPG Turns out that some cheap transistor c-b junctions are better pA diodes than some official, expensive picoamp diodes. I still want to demonstrate single-electron charge quantization at room temp using available parts. It should be just possible. John |