Murata Manufacturing Co. Ltd has released a surface mount type IEC 60384-141 Y12 class safety certified ceramic capacitor for low-profile power supplies.

Safety certified capacitors are placed at a power line input side in order to eliminate noise that builds up primarily in commercial AC power lines. These capacitors are usually of the lead type. However, the mounted height above the board surface is a problem because it hinders efforts to make low-profile devices and it limits component layout. And because lead type capacitors are through-hole mounted, the lead wires are exposed on the underside of the circuit board. A fixed amount of insulating distance between the exposed lead wires and the metal components of the device is required by safety standards, complicating spatial layout within a device.

Low profile structure

The capacitor uses a structure of plate-shaped terminals on a disc-shaped ceramic dielectric placed within a plastic mould to reduce the terminal thickness that is present with lead type capacitors, and this results in a mounted height of 2.5mm or less for the product. Furthermore, the component format enables reflow surface mount, and there is no longer a need to assure insulating distance at the underside of the board. This advances profile reduction for power supply devices subject to size limitations in compact AV equipment, LED illumination and 1U rack mounted equipment, for which spatial design has been difficult, Murata said.

20170713_Murata_Capacitors_01 Figure 1: Comparison of conventional lead-type capacitor and Murata's surface mount ceramic capacitor.

The Murata capacitor is ideal for AC-DC switching power supplies where low profile is needed, such as compact AV equipment, LED illumination, or 1U*3 rack mounted equipment.