Chip inductors are manufactured using semiconductor material. General specifications, performance specifications and features are all important parameters to consider when searching for chip inductors.

General Specifications for chip inductors include technology, core material, packing method and applications.  The follwoing are technology choices: 

• Solenoidal (standard) core

• Toroidal

• Bobbin core

• Wirewound

• Multilayer

• Laminated

Solenoidal cores are rod-shaped cores. Toroid chip inductors look exactly like doughnuts and come in various diameters, thickness, permeability and types depending upon the frequency range of interest. They have a high inductance for the physical space occupied. A bobbin core is a chip inductor with a core with the shape of a bobbin or spool.  Bobbin cores are available with and without leads and in the axial and radial form.

A wirewound inductor is an inductor with a core made of wound wires. Multilayer inductors are inductors constructed by layering the coil between the layers of core material.  The coil normally consists of a bare metal material (no insulation). This technology is normally referred to as "non-wirewound".

The inductance value can be made larger by adding additional layers for a giving spiral pattern. Laminated chip inductors are ferrite beads with a core that is constructed by stacking multiple laminations on top of each other.  The laminations can be of a variety of materials and thicknesses.

Core Materials and Packing

Coils can be wound on various core materials, the most popular being iron (or iron alloys, laminations, or powder) and ferrite, a black, nonconductive, brittle magnetic material. These are all ploys to multiply the inductance of a given coil by the "permeability" of the core material.

Core Materials

The core may be in the shape of a rod, a toroid (doughnut), or other shapes. Additional core materials include:

• Air

• Ceramic

• Phenolic

• MPP

• Molypermalloy powder

Packing Methods

• Tape reel

• Tray

• Tube

• Bulk pack

Common Applications

• Common mode choke

• General purpose

• High current

• High frequency

• Power inductor

• RF choke

Additional Features

Common features for chip inductors include shielding and molded case. A shielded inductor is designed for its core to contain the majority of its magnetic field. An inductor with a molded case has a case that has been formed via a moding process. 

Common molding processes include injection and transfer molding. Molded inductors typically have well defined body dimensions that consist of smooth surfaces and sharper corners as compared to other case types.

Standards

MIL-I-83446/10 - Inductors, chip, thick film, fixed.

SMD 5962-11017 - Inductors, smd, chip, thin film, tight tolerance, 0402.

Image Credits: 

API Technologies Corp - Spectrum Control | Coilcraft CPS