Fixed Inductors

Part Number	Description / PDF	Quantity
B82422A1333K108 TDK EPCOS	FIXED IND 33UH 105MA 4.5 OHM SMD	0
B82432T1472K000 TDK EPCOS	FIXED IND 4.7UH 800MA 220 MOHM	4149
B82464A4102M000 TDK EPCOS	FIXED IND 1UH 7A 9 MOHM SMD	4508
B82482M1472M000 TDK EPCOS	PCM120T-4R7M-D; 12.4X13.1X11.5 M	0
B82472G6472M000 TDK EPCOS	FIXED IND 4.7UH 2.5A 30 MOHM SMD	450
B82476A1334M000 TDK EPCOS	FIXED IND 330UH 600MA 810 MOHM	45
B82432C1394J000 TDK EPCOS	FIXED IND 390UH 80MA 15.3 OHM	0
B82464G4105M000 TDK EPCOS	FIXED IND 1MH 340MA 2.2 OHM SMD	1020
B78108S1154J009 TDK EPCOS	FIXED IND 150UH 280MA 2.8 OHM TH	0
B82477G4223M000 TDK EPCOS	FIXED IND 22UH 3.6A 38 MOHM SMD	1047
B82144B1824J000 TDK EPCOS	FIXED IND 820UH 310MA 3.7 OHM TH	0
B82422A3470K108 TDK EPCOS	FIXED IND 47NH 510MA 190 MOHM	0
B82144A2334J009 TDK EPCOS	FIXED IND 330UH 330MA 1.9 OHM TH	0
B82432C1824J000 TDK EPCOS	FIXED IND 820UH 60MA 28 OHM SMD	0
B82496C3150G000 TDK EPCOS	FIXED IND 15NH 420MA 400 MOHM	0
B82422A1183K100 TDK EPCOS	FIXED IND 18UH 155MA 2 OHM SMD	1174
B82442T1685K050 TDK EPCOS	FIXED IND 6.8MH 65MA 60.3 OHM	598
B82472G6103M000 TDK EPCOS	FIXED IND 10UH 1.9A 53 MOHM SMD	2527
B82432T1124K000 TDK EPCOS	FIXED IND 120UH 180MA 4.5 OHM	0
B82498F1332J000 TDK EPCOS	FIXED IND 3.3UH 100MA 3.3 OHM	0

Fixed Inductors

1. Overview

Fixed inductors are passive electronic components designed to store energy in magnetic fields when electrical current flows through them. Unlike variable inductors, their inductance values remain constant during operation. These components play critical roles in filtering, signal processing, energy storage, and electromagnetic interference (EMI) suppression across modern electronics, including power supplies, communication systems, and automotive electronics.

2. Main Types and Functional Classification

Type	Functional Characteristics	Application Examples
Wirewound Inductors	High precision, high current handling, low resistance	Power supplies, DC-DC converters
Chip Inductors	Compact SMD package, stable performance at high frequencies	Mobile devices, RF circuits
Ferrite Bead Inductors	Effective high-frequency noise suppression	EMI filtering in digital circuits
Thin-Film Inductors	Ultra-compact, high Q-factor, tight tolerance	5G communication modules, IoT devices

3. Structure and Composition

Typical fixed inductors consist of:

Magnetic Core: Made from ferrite, powdered iron, or composite materials to concentrate magnetic flux
Coil Structure: Copper wire wound around the core (enamelled or silver-plated)
Encapsulation: Molded resin or ceramic coating for mechanical protection and insulation
Terminations: Solder-coated ends for PCB mounting (for SMD types) or leaded connections

4. Key Technical Specifications

Parameter	Description	Importance
Inductance (L)	Measured in henrys (H), determines energy storage capacity	Defines filtering/energy storage performance
Rated Current (I_rated)	Maximum DC current before saturation	Prevents core saturation and failure
DC Resistance (DCR)	Resistance of coil windings	Affects efficiency and thermal performance
Self-Resonant Frequency (SRF)	Frequency where inductor behaves as capacitor	Limits effective operating frequency range
Q Factor	Quality factor indicating efficiency	Higher Q = lower energy losses

5. Application Fields

Consumer Electronics: Smartphones, laptops, LED drivers
Industrial Equipment: Motor drives, power inverters
Automotive Systems: ECU modules, EV battery management
Telecom Infrastructure: Base station filters, optical transceivers

6. Leading Manufacturers and Products

Manufacturer	Representative Product	Key Features
Murata	LQH3NPN100M	10 H, 1.2A, 1.8 1.4mm chip inductor
TDK	MLZ2012A100T	100MHz SRF, 1.0 1.25mm for RF circuits
Vishay	IHLP2525CZER1R0M	1 H, 12A, composite construction
Coilcraft	0402DC-103J	10 H, 5% tolerance, ultra-low profile

7. Selection Guidelines

Key considerations during selection:

Calculate required inductance based on switching frequency and ripple current
Verify rated current exceeds maximum operating current by 20-30%
Select SRF higher than circuit operating frequency
Consider package size vs. thermal dissipation requirements
For EMI suppression: Choose ferrite beads with impedance curves matching target frequencies

8. Industry Trends

Current development trends include:

Miniaturization: Sub-0.5mm size inductors for wearable devices
High-Frequency Operation: Components supporting >10GHz 5G applications
Integrated Solutions: Combined inductor-filter modules
Material Innovation: Nanocrystalline cores for higher saturation flux
Automotive Focus: AEC-Q qualified parts for EV/HEV systems