4A SMD Power Inductors:

We offer a wide range of semishielded, shielded, unshielded and wirewound SMD power inductors from multiple manufacturers.An SMD Inductor, or Surface Mount Device Inductor, has no wire leads on its ends. This type of inductor is mounted directly to the surface of a circuit board via a metal pad on each end of the device.An SMD inductor commonly comprises a small coil shaped much like a spring, made of an electrically conductive wire. Some SMD inductors have a core of some type at the centre of the coil. Depending on the material chosen to serve as a core, often ferrite based, and the size and density of the core itself, the operational properties of the coil can be altered to fit specific needs.How to choose a suitable deviceAs SMD power inductors are typically used for switching power supplies in portable applications like mobile phones, choosing a suitable device depends above all on its size. Circuit board space is at a premium, especially as ever more functionality, and an associated increase in current, is added to the phone.Other key criteria include the device’s inductance value at the power supply switching frequency, its coil DC resistance, the additional saturation current, the additional RMS current, the equivalent series impedance (ESR) and the Q factor. The choice of shielded or unshielded inductor type is also important, and depends on the application.Since chip inductor manufacturers rarely provide ESR and Q factor information, designers should ask them for it. The relationship between the inductance and the current given by the manufacturer is often limited to 25°C, so the relevant data within the desired operating temperature range should be obtained. The worst case is generally 85°C.