Automotive Electronics

Water-Repellant Capacitors for Automotive Systems

Murata Manufacturing Co., Ltd. has introduced the GXT series of water repellant capacitors for automobile infotainment systems and comfort equipment. Designed with a water repellant layer on a multilayer ceramic capacitor, the product conforms to the AEC-Q200 electrical parts standard for automotive applications.

The GXT series is available with voltage ratings of 4Vdc to 100Vdc and capacitance ratings from 1pF to 47µF. They are offered in two styles, temperature compensated devices with a maximum operating temperature of 125 degrees C and high dielectric constant models rated for operation to 85 degrees C.

In conjunction with advances in size reduction and surface mount increased density in electronic equipment, there remains a possibility of generating a fault in circuit operation due to ion migration in components by condensation in environments exposed to severe heat and humidity changes.

For that reason, Murata has applied a water repellant layer to the surface of a multilayer ceramic capacitor that conforms to the AEC-Q200 automotive electronic components standards and thereby introduced a water repellant capacitor that can mitigate ion migration due to condensation.

Regarding water repellant capacitors, the company has offered the GXM series for general electronic equipment and the GGM series for automotive powertrain and safety applications, and is now adding the GXT series for automotive infotainment systems and comfort equipment.

The structure of a water repellant capacitor

In the GXT series, a water repellant layer has been applied to the surface of the capacitor. This water repellant condition of the capacitor maintains water droplets in a scattered state, hindering growth of the condensed water drops that can connect the outside electrodes, and it thereby reduces the occurrence of ion migration.

Water repellant condition maintains droplets in a scattered state

In addition, the water repellant film on the surface of the capacitor suppresses the elution of outside electrode metal to a water drop (ionization).

Suppression of metal elution to water drop

In a wettability test using a water-soluble black marker , the water repellant condition of a processed component is clearly superior to that of a component without the Murata Water repellant Layer.

Note: The goal of this Murata component is reduction of ion migration, not complete prevention of the effect.

Wettability test using a water-soluble black marker (untreated components on left, water repellant processed components on right)