PB Design For high-frequency noise suppression, Ferrite chip beads are important components for functional or regulatory reasons. For the purpose of sensitive integrated circuits operation, DC bus having low noise is best.
The amount of noise that is emitted through the air or ports of electronic products are limited by guidelines nationally and internationally. Before regulatory testing, the selection of correct filtering components is very important because each testing round is time consuming and expensive.
Since frequency relationship vs true impedance is very complex and impedance in the datasheet is also given at a single frequency, right ferrite chip bead is not easy task to find.
This article guides about the ferrite chip bead basic operation and best ferrite chip bead selection for signal, power and mixed application.
Operation of Ferrite Chip Bead
In power supply lines high frequency noise can be filtered most effectively and cheaply by using ferrite chip beads. As far as intended frequency range is concerned they are highly resistive and passive devices as well.
In this range the signals magnitude are reduced when these are connected with power supply rail in series. For low-pass filter creation and supply line isolation from the noise of IC switching, they are used with decoupling capacitors in tandem near IC power inputs.
The resistive component is much higher in ferrite chip beads as compared with inductors. The dependency of ferrite chip bead impedance is much higher on DC bias.
There is a decrease in the inductive component of the ferrite chip bead for larger DC bias values. Therefore, at circuit operating point and at zero DC bias, it is highly important to check the impedance of ferrite chip beads.
Searching the Correct Ferrite Chip Bead for Your Supply Chain Requirements and Applications
The general rule for selecting noise filtering for a ferrite chip bead is to select chip bead in which rated current is 5 times higher as compared to the expected current in the application.
The reason for this is the impedance decreases as DC bias increases. At a frequency instead of decreasing the level of noise it is increasing so resonance must also be avoided.
To avoid this, at a given DC bias point the frequency response is viewed by simulating the filter capacitor and ferrite chip bead. The unwanted resonance peaks can be avoided by tuning the circuit. In Order to reduce noise to desirable levels, damping is required.
It’s good to check the availability as well as price of the part after the selection of properly functioning ferrite chip bead. It is useless you find the perfect component if it is out of stock and high prices. If first choice increases in price or becomes out of stock then the list of alternative parts is always helpful. For this reason automated online tools are of great importance.
The SourcingBot engineers have assembled all the required data for verifying the requirements of the supply chain, correct ferrite chip bead selection and the list of replacement parts. As an example, let’s take a look of Wurth ferrite chip bead at their page, found Ferrite Beads.
Many other things are also available in one place i.e. lab measured data, availability, similar parts, pricing, datasheet information and other resources. On their site we also have the access of match tables from which engineers easily present and calculate the most similar parts.
Simply comparing the parameters of the datasheet, replacement can be very easily found automatically. Similarity scores can also be found easily at the top of the table. The values can be very easily compared with the eye by using the table.
For the purpose of finding the best match mechanical dimensions, rated current, impedance, DC resistance and much more are compared. For an engineer, the cross-referencing of ferrite chip bead processes becomes much faster.
By using the SourcingBot tools, the procurement demands and the technical specifications of the project can be very easily met by an engineer. The technical specifications for every part and the suggested replacements for every part can be very easily calculated in one place.
By using SourcingBot, engineers can easily find replacement parts and part information for more than 5 million components. The components may be connectors, passives and semiconductors.