metal electrode leadless face (component) (MELF)
SMD components are usually designed in a rectangular package. In addition, there is also the cylindrical MELF design (Metal Electrode Leadless Face). Components that are designed in the MELF form always have two connections. They can be recognized by the fact that the two end faces of the component are surrounded by a contact material, which is used in SMT technology for soldering to the conductor tracks.
The MELF technique can be used for resistors and thermistors, but also for diodes, crystals and other components. It is often used for diodes, which are surrounded by a cylindrical glass body, which is equipped with contact surfaces on the end faces.
The MELF design comes in a variety of standardized sizes. The standard length is 5.8 mm with a diameter of 2.2 mm. In a smaller version, the MiniMELF, the length is 3.6 mm, the diameter is 1.4 mm, and components in the MicroMELF version are only 2.2 mm long and have a diameter of 1.1 mm. The power consumption of the different versions is 1 W, 0.25 W and 0.2 W.
The MELF components are characterized by good characteristic data, which are generally superior to those of the other designs.