Capacitors and ESD
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From: blanko on 18 Jan 2010 18:39 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
From: Tim Williams on 18 Jan 2010 20:23 Capacitor divider. Run the numbers. What's a human body, about 1nF and 10kV worst case? Not going to do much to anything over 0.1uF. Tim -- Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms "blanko" <electrone2(a)yahoo.com> wrote in message news:a4aad671-1468-404f-a8f6-5420a6bc99da(a)21g2000yqj.googlegroups.com... > 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 > > > >
From: John Larkin on 18 Jan 2010 21:44 On Mon, 18 Jan 2010 19:23:31 -0600, "Tim Williams" <tmoranwms(a)charter.net> wrote: >Capacitor divider. Run the numbers. > >What's a human body, about 1nF and 10kV worst case? Not going to do much to >anything over 0.1uF. > >Tim The common body model is 100 pF in series with 1.5K. That, charged to 10KV, dumps 10 volts into a 0.1 uF cap. Of course, it dumps most of that 10KV into a 10 pF cap. I tested some 0603 16 volt ceramic caps to see when they'd fail. At 120 volts, the limit of my supply, they were still OK. John
From: whit3rd on 18 Jan 2010 22:22 On Jan 18, 3:39 pm, blanko <electro...(a)yahoo.com> wrote: > Are capacitors ESD sensitive? Please explain. Yes, kinda, BUT if it's an electrolytic, it heals afterward, and if it's a ceramic, there isn't any permanent damage, and it goes back to 'normal' after a while (faster if it's hot). Only the ultra-thin MOS capacitors of IC processes are really likely to take permanent damage from a little bit of charge. Some of the high-density ceramics are piezoelectric, and those can turn nonlinear if you get 'em above the voltage rating. One manufacturer actually required the capacitance value to be measured BEFORE any verification of max sustainable voltage, so the units wouldn't fail incoming testing.
From: Tim Williams on 18 Jan 2010 23:34
"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message news:ot6al5pi072rjuve8kn52upk48m6c09d53(a)4ax.com... > I tested some 0603 16 volt ceramic caps to see when they'd fail. At > 120 volts, the limit of my supply, they were still OK. Of course, they'd be no good at bypassing at that voltage. The D-E curve (think B-H) is going to be flat as Kansas. Tim -- Deep Friar: a very philosophical monk. Website: http://webpages.charter.net/dawill/tmoranwms |