The KEMET Organic Capacitor (KO-CAP) is a solid electrolytic capacitor with a conductive polymer cathode capable of delivering very low ESR and improved capacitance retention at high frequencies. KO-CAP combines the low ESR of multilayer ceramic, the high capacitance of aluminium electrolytic and the volumetric efficiency of tantalum into a single surface mount package. Unlike liquid electrolyte based capacitors, KO-CAP has a very long operational life and high ripple current capabilities, The T591/T598 High Humidity/High Temperature Polymer Electrolytic Series delivers higher capacitance and ESR stability under harsh environmental conditions. Enhancements to the design and selected material upgrades were introduced to deliver 500 hours (T591) or 1,000 hours (T598) at 85°C/85% RH rated voltage and to fully comply with the AEC–Q200 Qualification Testing. These series are manufactured in an ISO TS 16949 certified plant and are subjected to PPAP/PSW and change control.