Fixed Inductors

Part Number	Description / PDF	Quantity
B82473A1334K000 TDK EPCOS	FIXED IND 330UH 400MA 1.26 OHM	681
B78148E1101M009 TDK EPCOS	FIXED IND 100NH 7.3A 15 MOHM TH	0
B82464A4473K000 TDK EPCOS	FIXED IND 47UH 1.5A 140 MOHM SMD	630
B82472G6332M000 TDK EPCOS	FIXED IND 3.3UH 2.85A 23 MOHM	3658
B78148E1333J009 TDK EPCOS	FIXED IND 33UH 1.05A 550 MOHM TH	0
B78108E1221M000 TDK EPCOS	FIXED IND 220NH 5.9A 19 MOHM TH	5034
B82144B2122K000 TDK EPCOS	FIXED IND 1.2UH 4.25A 44 MOHM TH	902
B82132A5302M000 TDK EPCOS	FIXED IND 3UH 3A 35 MOHM TH	1897
B82559A4222A020 TDK EPCOS	FIXED IND 2.2UH 1.2 MOHM SMD	400
B82432T1394K000 TDK EPCOS	FIXED IND 390UH 110MA 13 OHM SMD	0
B78108S1272K000 TDK EPCOS	FIXED IND 2.7UH 940MA 260 MOHM	0
B82496C3689J000 TDK EPCOS	FIXED IND 6.8NH 700MA 150 MOHM	906
B82472G6223M000 TDK EPCOS	FIXED IND 22UH 1.45A 91 MOHM SMD	0
B82442H1155K000 TDK EPCOS	FIXED IND 1.5MH 100MA 16 OHM SMD	0
B82464G4152M000 TDK EPCOS	FIXED IND 1.5UH 7A 9 MOHM SMD	0
B82141A1183K009 TDK EPCOS	FIXED IND 18UH 350MA 810 MOHM TH	0
B82442A1152K000 TDK EPCOS	FIXED IND 1.5UH 1.6A 32 MOHM SMD	0
B82498F1562J000 TDK EPCOS	FIXED IND 5.6UH 85MA 4.3 OHM SMD	0
B82144B2473J000 TDK EPCOS	FIXED IND 47UH 1.7A 270 MOHM TH	697
B78108E1332K000 TDK EPCOS	FIXED IND 3.3UH 3.05A 73 MOHM TH	5000

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