Ferrite Beads also known as ferrite chokes are passive devices and they are used to constrict high-frequency signals in electronic components. The ferrite becomes resistive over its intended frequency range and uses up the noise energy in the form of heat.
How
dotheferritebeadswork?
The ferrite bead is connected in series with the power supply rail and is often combined with the capacitors to ground on either side of the bead. This then forms a low-pass filter network, further reducing the high-frequency power supply noise. Use SPICE (Simulation Program with Integrated Circuit Emphasis) or another similar tool to ensure any anti-resonance peaks caused by ferrite or PCB inductive structure does not violate the target impedance limit.
Ferrite
Beadscomeintwocategories:
High-Q Beads - typically used as resonators and must not be used in power isolation circuits
Low-Q Beads - these are also called absorptive beads and they are lossy and make good filter networks because they are designed to absorb high-frequency noise currents and dissipate it as heat
What
toconsiderwhenchoosingFerriteBeads?
Make sure that any voltage drop does not cause the target supply rail to fall below the recommended operating conditions of the device
The ferrite bead is inductive, therefore do not use it with High-Q decoupling capacitors
Applying ferrite beads correctly can be an effective and inexpensive way to reduce high-frequency noise and switching transients
Where
areFerriteBeadsused?
Eliminating high-frequency EMI noise on any circuit design
Anti EMI, Control Signals, DC/DC Converter, Fast Bus Signals, HDD, High Current, High Frequency, High Speed, Line Filter, LVDS, Power Supply, RS232, RS422, USB 2.0
Anti EMI, Control Signals, DC/DC Converter, Fast Bus Signals, HDD, High Current, High Frequency, High Speed, Line Filter, LVDS, Power Supply, RS232, RS422, USB 2.0
Anti EMI, Control Signals, DC/DC Converter, Fast Bus Signals, HDD, High Current, High Frequency, High Speed, Line Filter, LVDS, Power Supply, RS232, RS422, USB 2.0
Description:
From Wurth Elektronik, these ferrite beads are used
for suppressing high-frequency interference in electronic circuits. The chokes support a constant current of 3A, though 5A is possible for short periods. Different core materials result in different suppression profiles. These through-hole ...
Description:
Excellent anti-EMI properties and low DC resistancePlaced very
close next to the interference source even with smallest size 0402, maximum impedance 1000ΩReliable Ni-Sn electrodes Ideal for data line filtering and voltage de-couplingHigh rated current up to 6A Recommended for reflow ...
Description:
Excellent anti-EMI properties and low DC resistancePlaced very
close next to the interference source even with smallest size 0402, maximum impedance 1000ΩReliable Ni-Sn electrodes Ideal for data line filtering and voltage de-couplingHigh rated current up to 6A Recommended for reflow ...
Description:
BLM series ferrite beads from Murata do not
require a ground connection and are ideal for use in circuits with unstable ground lines. At noise frequencies, these ferrite beads are designed to function nearly as resistors, leaving signal wave forms ...