Murata Power Solutions has developed a capacitor able to withstand the extremely high temperatures experienced by equipment located in severe environments such as the engine compartment of an automobile.
To improve the fuel economy of an automobile, a DC motor drive is used to optimise control of the power train control system. A capacitor is used to suppress the electrical noise generated by this DC motor, but the automobile control equipment is mounted in an extreme environment, where temperatures can approach 200°C for short periods of time. Consequently, a very high degree of durability is needed for a capacitor deployed in this environment.
Featuring a newly developed heat resistant resin coating around a highly heat resistant multilayer ceramic capacitor, Murata’s newly developed RHS capacitors can be used at temperatures up to 200 °C and as low as -55 °C.
The capacitors comply with AEC-Q200 and their lead wires can be soldered or crimped to position them close to a noise-generating source for optimum performance and effectiveness. The RHS capacitors also pass the extreme surge test of the ISO7637-2 standard.
Capacitance values from 100 pF to 0.01 uF will be available, and the lineup initially includes 200 Vdc and 500 Vdc rated products, with the voltage range being expanded during 2017. At temperatures above 150°C, voltage derating is applied, so for example, a 500 V rated capacitor is rated at 125 V when used at 200°C.
Determined by the combination of rated voltage and capacitance value, the capacitors measure 4.0 × 3.5 mm or 5.5 × 4.0 mm, with lead centres being 2.5 or 5.0 mm as appropriate.
Full production of the RHS capacitors begins in May 2017 and Murata expects to expand and diversify sales of the products for equipment mounted in a variety of high temperature environments such as engine rooms.