There are four main types of SMD inductors, namely wound type, stacked type, woven type, and thin film chip type inductors. The commonly used types are wound and stacked. The former is a product of miniaturization of traditional wound inductors; The latter is made using multi-layer printing technology and stacked production process, which is smaller in volume than wound type chip inductors and is a key product developed in the field of inductance components.

1. Winding type

It is characterized by a wide range of inductance (mH ～ H), high precision of inductance, small loss (i.e. large Q), large allowable current, strong inheritance of manufacturing process, simplicity, low cost, etc., but its disadvantages are limited in further miniaturization. Ceramic core wound wire inductors can maintain a stable inductance and a relatively high Q value at such high frequencies, thus occupying a place in high-frequency circuits.

The NL series inductors of TDK are wound, with an accuracy of 0.01~100uH, 5%, and high Q value, which can meet general needs.

NLC type is suitable for power circuits, with a rated current of up to 300mA; The NLV type has a high Q value, is environmentally friendly (recycled plastic), and can be interchanged with NL; NLFC has a magnetic screen, suitable for power cords.

2. Stacked type

It has good magnetic shielding, high sintering density, and good mechanical strength. The shortcomings are low qualification rate, high cost, small inductance, and low Q value.

Compared with wound inductor, it has many advantages: small size, favorable for circuit miniaturization, closed magnetic circuit, no interference with surrounding components, and no interference from adjacent components, which is conducive to high-density installation of components; Integrated structure, high reliability; Good heat resistance and weldability; Regular in shape, suitable for automated surface installation production.

TDK's MLK inductor has a small size, good solderability, magnetic screen, high-density design, single chip structure, and high reliability; The MLG type has a low inductance and uses high-frequency ceramics, suitable for high-frequency circuits; MLK type operating frequency 12GHz, high Q, low inductance (1n~22nH)

3. Film type

It has the characteristics of maintaining high Q, high accuracy, high stability, and small volume in the microwave frequency band. The internal electrodes are concentrated on the same layer, with a concentrated magnetic field distribution, which ensures that the device parameters do not change much after installation and exhibit good frequency characteristics above 100MHz.

4. Woven type

The characteristic is that the unit volume inductance at 1MHz is larger, smaller, and easier to install on the substrate than other chip inductors. Micro magnetic components used for power processing.

In practical applications, it is necessary to choose the application according to the situation, consider the application effect, and also consider the material cost.