The Defense Logistics Agency (DLA) accepted KEMET’s X7R dielectric MIL-PRF-32535 for "M" and "T" reliability levels. The company offers both Class-I and Class-II base metal electrode (BME) multilayer ceramic capacitors (MLCCs) qualified for defense and aerospace applications by the DLA.
According to the company, MIL-PRF-32535 is the first DLA capacitor specification for defense and aerospace that capitalizes on BME technology. In December 2017, KEMET announced DLA approval for C0G and BP Class-I dielectrics targeting critical timing, tuning, pulse, ac, and transient-voltage-suppression applications where capacitance stability may be a concern.
With the DLA approval of the X7R Class-II dielectric, design engineers now have access to ceramic capacitors that offer up to a 55-fold increase in capacitance values as compared with the offerings under traditional specifications using precious metal electrodes (PME). These capacitors are well-suited for decoupling, bypass, filtering, and bulk storage for military, avionics, and space applications.
MIL-PRF-32535 is also the first DLA specification to recognize a flexible termination option, according to KEMET. Flexible termination utilizes a pliable conductive silver epoxy in the termination system. Adding this epoxy layer inhibits the transfer of board stress to the rigid ceramic body, therefore mitigating flex cracks that can result in low insulation resistance or short circuit failures.
These Class-I and Class-II capacitor ranges were qualified through the stringent requirements of the MIL-PRF-32535 specification.