Reference Specification DES Series High Temperature Low Loss Lead Type Disc Ceramic Capacitors for General Purpose Product specifications in this catalog are as of Dec. 2017, and are subject to change or obsolescence without notice. Please consult the approval sheet before ordering.Please read rating and Cautions first. Reference only CAUTION 1. OPERATING VOLTAGE When DC-rated capacitors are to be used in AC or ripple current circuits, be sure to maintain the Vp-p value of the applied voltage or the Vo-p which contains DC bias within the rated voltage range. When the voltage is started to apply to the circuit or it is stopped applying, the irregular voltage may be generated for a transit period because of resonance or switching. Be sure to use a capacitor within rated voltage containing these irregular voltage. When DC-rated capacitors are to be used in input circuits from commercial power source (AC filter), be sure to use Safety Recognized Capacitors because various regulations on withstand voltage or impulse withstand established for each equipment should be taken into considerations. Voltage DC Voltage DC+AC Voltage AC Voltage Pulse Voltage(1) Pulse Voltage(2) Positional Vo-p Vp-p Vo-p Vp-p Vp-p Measurement 2. OPERATING TEMPERATURE AND SELF-GENERATED HEAT Keep the surface temperature of a capacitor below the upper limit of its rated operating temperature range. Be sure to take into account the heat generated by the capacitor itself. When the capacitor is used in a high-frequency current, pulse current or the like, it may have the self- generated heat due to dielectric-loss. The frequency of applied voltage should be in less than 300kHz in sine wave. Applied voltage should be the load such as self-generated heat is within 15 C on the condition of atmosphere temperature 25 C. When measuring, use a thermocouple of small thermal capacity-K of 0.1mm and be in the condition where capacitor is not affected by radiant heat of other components and wind of surroundings. Excessive heat may lead to deterioration of the capacitors characteristics and reliability.(Never attempt to perform measurement with the cooling fan running. Otherwise, accurate measurement cannot be ensured.) 3. FAIL-SAFE When capacitor would be broken, failure may result in a short circuit. Be sure to provide an appropriate fail-safe function like a fuse on your product if failure would follow an electric shock, fire or fume. 4. LOAD REDUCTION AND SELF-GENERATED HEAT DURING APPLICATION OF HIGH-FREQUENCY AND HIGH-VOLTAGE Since the heat generated by the low-dissipation capacitor itself is low, its allowable power is much higher than the general B characteristic. However, in case such an applied load that the self-heating temperature is 20 C at the rated voltage, the allowable power may be exceeded. Therefore, when using the low-dissipation capacitors in a high-frequency and high-voltage circuit with a frequency of 1kHz or higher, make sure that the Vp-p values including the DC bias, do not exceed the applied voltage value specified in Table 1. Also make sure that the self-heating temperature (the difference between the capacitors surface temperature and the capacitors ambient temperature) at an ambient temperature of 25 C does not exceed the value specified in Table 1. As shown in Fig. 2, the self-heating temperature depends on the ambient temperature. Therefore, if you are not able to set the ambient temperature to approximately 25 C, please contact our sales representatives or product engineers. <Table 1> Allowable Conditions at High-frequency Allowable Conditions at High-frequency *3 DC Capacitors Temp. Self-heating Temp. Rated Applied Voltage Ambient Char. Voltage (max.) Temp. *2 (25 C Ambient Temp.) *1 500V 500Vp-p 15 C max. D -25 to +85 C 800Vp-p 15 C max. 1kV 1000Vp-p 5 C max. *1 Fig. 1 shows the relationship between the applied voltage and the allowable self-heating temperature regarding 1kV rated voltage of the DES series D characteristic. *2 When the ambient temperature is 85 to 125 C, the applied voltage needs to be further reduced. If the low-dissipation capacitors needs to be used at an ambient temperature of 85 to 125 C, please contact our sales representatives or product engineers. *3 Fig. 3 shows reference data on the allowable voltage-frequency characteristic for a sine wave voltage. EGD24E 1 / 17