A 220 microfarad capacitor has been promised by the ceramic capacitor industry for more then 2 years now, with a promise of it being 18 months away; with X5R prototypes being developed for mass production. However it is no mystery that the time frame for this development, so critical for the advancement of ceramic capacitor technology further into the electrolytic market segment (worth $7 billion USD). Key technology developments in high capacitance MLCC occurred in 1993, 1995 and 1998 with respect to capacitance value per cubic centimeter of dielectric; since then the additional developments have been in performance characteristics of the finished capacitors at various operating temperatures, voltages and frequencies; with technology focused on eliminating unwanted affects inherent in the ceramic. To that end, PCI Magazine posed the following question to our readers…
We patiently await the production of a 220-microfarad ceramic chip capacitor- why do you think such a product is taking so long to mass produce?
This question prompted a flurry of responses on the subject- 60% of respondents cited that technological hurdles with a 220 microfarad ceramic chip capacitor could not as of yet be overcome to justify its mass production. 25% said that a 220 microfarad MLCC was possible to produce today, but that the costs to produce, including raw materials, processing costs and low yield ratios are too expensive when compared to competing technologies in aluminum and tantalum technology. 15% of respondents noted that the total available market in the 220-microfarad “surface mount” portion of the electrolytic business was not large enough to justify the development costs.
Those that noted technical difficulties outlined come key technical hurdles associated with producing a 220 microfarad MLCC, with numerous respondents point toward the projected loss in effective capacitance when DC bias voltage is applied to such a part especially when packaged in a usable 1210 or 1206 (EIA) case size. Others noted the very poor voltage coefficient and alarming piezolectric parasitics of such a device. And that “Thinning the (ceramic) slip will make this already ghastly set of problems worse.” Others still pointed toward the mechanical instability of such a device, noting that so many layers in such a small device will result in a high degree of cracking. Those that believed such a device was possible to produce over time, noted that beyond the technical limitations was the bare fact that the current costs to produce for MLCC at such a high capacitance level would be too high to compete with the costs of alternative capacitor dielectrics, such as tantalum and aluminum, who ultimately have much higher yield ratios then would be possible in such a high layer count part. Respondents also noted that the total available market at 220 microfarad in a comparable part- a surface mount tantalum chip or a solid polymer aluminum capacitor- was too small to justify the investment in development costs.
Additional Resources: (1) Ceramic Capacitors: World Markets, Technologies & Opportunities: 2009-2014 ISBN # 1-893211-25-8 (December 2009) (2) (2) BME MLCC: Global Markets, Technologies & Opportunities: 2005-2010 ISBN # 1-893211-74-6 (2005)