Fixed Inductors

Part Number	Description / PDF	Quantity
B78148S1824J000 TDK EPCOS	FIXED IND 820UH 140MA 12 OHM TH	0
B82422A1473K100 TDK EPCOS	FIXED IND 47UH 85MA 7 OHM SMD	5290
B82476A1684M000 TDK EPCOS	FIXED IND 680UH 400MA 1.6 OHM	0
B82479A1103M000 TDK EPCOS	FIXED IND 10UH 4.3A 32 MOHM SMD	709
B82498F3101J000 TDK EPCOS	FIXED IND 100NH 450MA 280 MOHM	5810
B78108E1472K000 TDK EPCOS	FIXED IND 4.7UH 2.75A 85 MOHM TH	4466
B82422T1221K000 TDK EPCOS	FIXED IND 220NH 450MA 200 MOHM	3504
B82475A1103M000 TDK EPCOS	FIXED IND 10UH 2.6A 60 MOHM SMD	0
B82442T1825K000 TDK EPCOS	FIXED IND 8.2MH 54MA 80.6 OHM	0
B82144B2682K000 TDK EPCOS	FIXED IND 6.8UH 2.75A 95 MOHM TH	655
B82422H1153K000 TDK EPCOS	FIXED IND 15UH 390MA 720 MOHM	1290
B82559B4222A019 TDK EPCOS	FIXED IND 2.2UH 27.2A 1.8 MOHM	400
B82442A1564K000 TDK EPCOS	FIXED IND 560UH 110MA 6.8 OHM	0
B82498F3820J000 TDK EPCOS	FIXED IND 82NH 500MA 190 MOHM	3338
B82422T1121K008 TDK EPCOS	FIXED IND 120NH 450MA 150 MOHM	0
B82477P4683M000 TDK EPCOS	FIXED IND 68UH 2.35A 98 MOHM SMD	534
B82476B1684M100 TDK EPCOS	FIXED IND 680UH 430MA 1.6 OHM	606
B82476A1332M000 TDK EPCOS	FIXED IND 3.3UH 5.4A 13.5 MOHM	705
B82477G4652M000 TDK EPCOS	FIXED IND 5.6UH 6.7A 14.2 MOHM	0
B82498F3151J001 TDK EPCOS	FIXED IND 150NH 400MA 420 MOHM	3369

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