THE SERVICE LIFE OF E-CAPS
AN E-CAP'S "TRUE" SERVICE LIFE IS OF VITAL IMPORTANCE TO DESIGNERS. HOWEVER, BECAUSE MANUFACTURERS DO NOT ALL DEFINE THIS PARAMETER UNIFORMLY, CODICO THINKS IT'S TIME TO PROVIDE YOU WITH SOME IMPORTANT FACTS:
RUBYCON defines the service life (i.e., the "guaranteed lifetime") of its e-caps as the length of time that they can be operated under full load (max. permissible ripple current) and at maximum temperature without a single unit falling outside the specified parameters.
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In other words, RUBYCON e-caps can be fully loaded without having to plan a "reserve factor" for your design.
Other manufacturers (e.g., many in China and
Europe) frequently specify the service life without indicating a current load value, which means you won't have all the facts needed to judge actual performance. We all know that current flow causes self heating in elcaps, and that this can have a significant impact on the service life. However, without a value for current load there is often no way to accurately calculate the expected lifetime for certain operating conditions.
E-caps also frequently come with a manufacturer-specified usable lifetime, which generally assumes a certain failure rate. For your application, that means the use of several e-caps will increase the chance of a failure or that a device will stop performing within the specified parameters (e.g., ripple voltage in power supplies). Unfortunately, e-cap manufacturers do not use uniform criteria for defining failures, with some accepting capacitance losses as high as 50% as being within tolerance.
If you'd like to find out more about using RUBYCON e-caps and the advantage of working with a "true" service life, just send CODICO your design parameters: ambient temperature, current, required service life, etc. We will help you select the optimal solution for your application!
Thomas Jell, EXT 25
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