Fixed Inductors

Part Number	Description / PDF	Quantity
B82473M1224K000 TDK EPCOS	FIXED IND 220UH 490MA 960 MOHM	0
B82442T1125K000 TDK EPCOS	FIXED IND 1.2MH 140MA 12.6 OHM	0
B82144F1155J000 TDK EPCOS	FIXED IND 1.5MH 230MA 6.4 OHM TH	0
B82422A3180K100 TDK EPCOS	FIXED IND 18NH 640MA 120 MOHM	0
B82144B2683J000 TDK EPCOS	FIXED IND 68UH 1.5A 350 MOHM TH	874
B82498F3821G001 TDK EPCOS	FIXED IND 820NH 180MA 1.9 OHM	0
B82442T1394K000 TDK EPCOS	FIXED IND 390UH 260MA 3.7 OHM	0
B82477G4683M000 TDK EPCOS	FIXED IND 68UH 2.1A 120 MOHM SMD	90
B82442T1825K050 TDK EPCOS	FIXED IND 8.2MH 54MA 80.6 OHM	0
B82462A4153K000 TDK EPCOS	FIXED IND 15UH 900MA 210 MOHM	742
B82479A1154M000 TDK EPCOS	FIXED IND 150UH 1.5A 250 MOHM	173
B82141A1472K009 TDK EPCOS	FIXED IND 4.7UH 530MA 360 MOHM	0
B82496C3390J000 TDK EPCOS	FIXED IND 39NH 300MA 800 MOHM	4723
B78148S1475J000 TDK EPCOS	FIXED IND 4.7MH 55MA 78 OHM TH	12436
B78108S1472K009 TDK EPCOS	FIXED IND 4.7UH 820MA 340 MOHM	0
B82432T1223K000 TDK EPCOS	FIXED IND 22UH 450MA 700 MOHM	5447
B82559A9153A020 TDK EPCOS	FIXED IND 15UH 4.95 MOHM SMD	498
B78108E1221M009 TDK EPCOS	FIXED IND 220NH 5.9A 19 MOHM TH	198
B82476A1154M000 TDK EPCOS	FIXED IND 150UH 1A 330 MOHM SMD	687
B78148S1104J009 TDK EPCOS	FIXED IND 100UH 370MA 1.7 OHM TH	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