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Murata’s water repellant capacitor for car infotainment systems

2017-10-11 | Return

Overview

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*1 electrical parts standard for automotive applications. This product is now in mass production.

Background

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*2 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.

Features

The structure of a water repellant capacitor is illustrated in Fig. 1. 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 (Fig. 2), hindering growth of the condensed water drops that can connect the outside electrodes, and it thereby reduces the occurrence of ion migration. In addition, the water repellant film on the surface of the capacitor suppresses the elution of outside electrode metal to a water drop (ionization). In a wettability test using a water-soluble black marker (Fig. 4), 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.)

Fig. 1: Structural example of the water repellant capacitor

Fig. 2: Water repellant condition maintains
droplets in a scattered state.

Fig. 3: Suppression of metal
elution to water drop

Fig. 4: Wettability test using a water-soluble black marker
(untreated components on left, water repellant processed components on right)

Applications

Examples: automotive infotainment systems, comfort equipments
(car navigations, audio equipments, etc.)

Part number

Example: GXT32ER60J107ME13 (series name: GXT)

See this page for the GXT series lineup.

Electrical characteristics

Temperature characteristics	X5R, X6S, X7R, X7S, C0G
Rated Voltage	4~100Vdc
Capacitance tolerances	±0.25pF, ±0.5pF, ±5%, ±10%, ±20%
Usage temperature range	-55~85°C (X5R), -55~105°C (X6S), -55~125°C (X7R, X7S, C0G)

External size

LW size

0402 inch size: 1.0×0.5mm (T=0.5mm)
0603 inch size: 1.6×0.8mm (T=0.8mm)
0805 inch size: 2.0×1.25mm (T=1.25mm)
1206 inch size: 3.2×1.6mm (T=1.6mm)
1210 inch size: 3.2×2.5mm (T=2.0, 2.5mm)

Explanation of terms

1. AEC-Q200:
Test standards for reliability sought in automotive electrical parts, as decided by the Automotive Electronics Council.

2.Ion migration:
When voltage is applied while water is present between the electrodes, the metal of the anode will ionize and shift to the cathode, and the receiving of electrons at the cathode results in precipitation of the metal. The electrochemical phenomenon can lead to a short.

Source：http://www.murata.com/