Capacitor Life And Rating Application (CLARA)

The results will comprise part numbers having the target capacitance value and the next available capacitance for the same or higher input voltage, A_RMS, temperature, etc.

The criteria checkbox for reference standard is OR, and therefore shows all results having AEC Q-200D OR IEC 60384-14. If you look for an X or Y capacitor with AEC Q-200D compliance, select the required class in “External Approval” and click the checkbox of AEC Q-200D in “Reference Standard.”

“Simple Search” executes a search based on capacitor parameters and not application parameters. Suppose you insert 105 °C and 470 V DC. In that case, it will result in all part numbers having equal or higher temperature as maximum temperature AND all capacitors having equal or higher rated voltage than 470 V DC (Note: Rated Voltage is a parameter given usually at 85 °C).

“Advance Search Application Based” is the better module for this case. You can insert application parameters combined with some capacitor parameters.

Firstly, it is necessary to do a search, even with the full part number, and click search. On the list of part numbers, click the left check box of the desired part numbers and then click confirm. These are the selected ones for the simulation. You can repeat this process with other different part numbers up to a total of four parts. Then click “Simulate” when you want to access the simulation module.

There may be an over-rated condition above the given specification. Or the selected product is an EMI suppression capacitor. We do not provide lifetime statements for these EMI suppression capacitors because they are typically exposed to unexpected network disturbances that can make the lifetime statements no longer applicable.

This is the reliability function for the given lifetime expectation. For example, 95% for a lifetime of 100,000 h, means that after this 100,000 h, at least 95% of the components could have survived the given conditions. For detailed information, refer to Data Book – General Information – Quality.

Info buttons contain detailed information of the meaning of every parameter for better understanding. There is more information in the help file about waveform types and their conversion into input parameters.

There may be an over-rated condition above the given specification. Or the selected product is an EMI suppression capacitor. We do not provide lifetime statements for these EMI suppression capacitors because they are typically exposed to unexpected network disturbances that can make the lifetime statements no longer applicable.

The tool selects the worst case for the simulation of voltage stress. For thermal simulation, it is necessary to input the frequency harmonic spectrum; otherwise, it is assumed that there is no thermal stress beyond the input ambient temperature.

The models work under typical operation ranges. Out of this, they are not reliable or even not valid. They are estimated for the range of operation. In case of brief over-voltages or over-temperatures, we recommend checking the datasheet and/or contacting your sales channel for a customized feasibility check.

CLARA tool warns in case the self-heating is somehow higher than a certain given level. A very high self-heating could not necessarily harm the component if the ambient temperature is low enough and if there is no degradation of a parameter during the capacitor life that increases such a self-heating value.

Also, the self-heating estimation is based on our lab testing, with natural cooling and single capacitor test; no other heat source is considered that could influence a different R_th. We strongly recommend a real application test to monitor the key parameters (temperature, current, voltage, waveforms) for all cases, especially those where conditions are close to the limits.

Every part number is characterized for a frequency range, which we consider to have a homogeneous current distribution in the winding element. Therefore, power losses and dissipation follow the given calculations. CLARA makes a simple extrapolation of the curves based on the latest two frequency points. Let’s have a closer look on what will happen above such a frequency in a real application: These cases should be carefully evaluated via FEA simulation and a real test regarding thermal losses and dissipation with specific boundary conditions in the PCB.