SMD Power Inductor

Introduction to SMD Power Inductors
Chip inductors, also known as power inductors, high current inductors and surface mount high power inductors. It has the characteristics of miniaturization, high quality, high energy storage and low resistance.
Inductance in general electronic circuits is an air-core coil, or a coil with a magnetic core, which can only pass a small current and withstand a low voltage. The power inductors also have air-core coils and magnetic cores. The main feature is that they are wound with thick wires and can withstand tens, hundreds, thousands, or even tens of thousands of amps. Power SMD inductors are divided into two types with magnetic cover and without magnetic cover, mainly composed of magnetic core and copper wire. It mainly plays the role of filtering and oscillation in the circuit.

Classification of Chip Inductors
There are mainly 4 types of chip inductors, namely wire wound type, multilayer type, braided type and film chip inductors. Commonly used are two types of winding type and laminated type. The former is a product of the miniaturization of traditional wire-wound inductors; The latter is produced by multi-layer printing technology and laminated production process, and its volume is smaller than that of wire-wound chip inductors. It is a key product developed in the field of inductance components.

Wire Wound Chip Inductors
It is characterized by a wide range of inductance (mH～H), high inductance accuracy, small loss (that is, large Q), large allowable current, strong inheritance of manufacturing process, simplicity, and low cost. But the disadvantage is that it is limited in further miniaturization. Ceramic-core wirewound chip inductors can maintain stable inductance and a relatively high Q value at such a high frequency, so they occupy a place in high-frequency circuits.
TDK's NL series inductors are wire wound, 0.01~100uH, 5% accuracy, high Q value, which can meet general needs.
NLC type is suitable for power supply circuit, the rated current can reach 300mA; NLV type is high Q value, environmentally friendly (recycled plastic), and can be interchanged with NL; The NLFC has a magnetic screen and is suitable for power cords.

Multilayer Chip Inductors
It has good magnetic shielding properties, high sintering density and good mechanical strength. The disadvantages are low pass rate, high cost, small inductance, and low Q value.
It has several advantages over wirewound chip inductors: The small size is conducive to the miniaturization of the circuit, the magnetic circuit is closed, it will not interfere with the surrounding components, and it will not be disturbed by the adjacent components, which is conducive to the high-density installation of components; Integrated structure, high reliability; good heat resistance and solderability; Regular shape, suitable for automatic surface mount production.
TDK's MLK inductor has small size, good solderability, magnetic shield, high-density design, monolithic structure, and high reliability; The MLG type has a small inductance value and uses high-frequency ceramics, which is suitable for high-frequency circuits; the MLK type has a working frequency of 12GHz, high Q, and low inductance value (1n~22nH)

Thin Film Chip Inductors
It has the characteristics of maintaining high Q, high precision, high stability and small size in the microwave frequency band. The internal electrodes are concentrated on the same layer, and the magnetic field distribution is concentrated, which can ensure that the device parameters do not change much after mounting, and exhibit good frequency characteristics above 100MHz.

Braided Chip Inductors
The characteristic is that the inductance per unit volume at 1MHz is larger than other chip inductors, the volume is small, and it is easy to install on the substrate. Miniature magnetic components for power handling.