Aluminum electrolytic capacitors can be broadly divided into three types, based on the cathode material and the structure. Murata’s aluminum capacitors are all-solid multilayer polymer aluminum capacitors (the ECAS series)(Fig. 1).
Other varieties of aluminum capacitors include can-type wrapped aluminum capacitors that use either an electrolyte or a polymer as the cathode. What sets ECAS series capacitors apart are the high conductivity of the conductive polymer used as the cathode and the multilayer (laminated) structure of the aluminum elements. These make possible the lowest ESR obtainable among electrolytic capacitors.
ECAS series capacitors also achieve large capacitances, and the capacitance remains stable when DC voltage is applied due to the lack of DC bias. Thus, the major features of the ECAS series are low ESR, high capacitance, and stable capacitance.