Parameters to choose the right inductor for your design!
Being part of the most common and widely used passive electronic components, an inductor is a two-terminal electrical device that stores energy in a magnetic field. Inductors are basically made of a simple coil of wire, often wound around a core made of either a magnetic metal or air. They are commonly used in filters, transformers, tuning circuits, energy storage, impedance matching, sensors and more.
The most important step when selecting an inductor is to understand your specific application, then there are more important parameters such as inductance, tolerance and DC resistance that should be considered to improve the performance and efficiency of your design.
In this blog, we will explore the main inductor parameters, their definitions and general recommendations. Understanding the following parameters will help you to determine if the inductor you’re planning to use is the right one!
1) Quality Factor (Q)
The Quality Factor is the ratio of the reactance of the inductor to its resistance. Inductors are not purely inductive, their resistance causes energy loss and this can limit the performance of an inductor. Hence, the higher the Q factor, the lower the rate of energy loss.
2) Self-Resonant Frequency or SRF
The low distributed capacitance between the inductor terminals causes the inductor to have a self-resonant frequency (SRF). The SRF is the frequency at which an inductor stops working as an inductor. Designers should select an inductor with an SRF that is higher than the operating frequency.
3) Saturation Current
The saturation current is the current value at which the conductor can not take in any more magnetic flux. At this point, the inductance will drop at a specified value. Similar to the SRF, the saturation current must be significantly higher than the maximum current that will pass through the inductor.
4) DC Resistance or DCR
The DC resistance is the resistance component of the coil. A high DCR will cause high losses, so it is always better to select an Inductor with low DCR value. It is important to consider the acceptable DCR of the inductor according to your application.
Tolerance indicates how much the inductance can vary from the nominal value. Datasheets usually provide a tolerance percentage, high-tolerances are not desired but in the end, the tolerance should be selected based on your application.
We hope that this blog helps you to get started in selecting an inductor to use in your next PCB project! You can explore our available models for inductors here.
If you have any comments or questions, feel free to add them in the comment section.