Fixed Inductors

Part Number	Description / PDF	Quantity
B82422T1333J000 TDK EPCOS	FIXED IND 33UH 70MA 5.6 OHM SMD	0
B82476B1474M100 TDK EPCOS	FIXED IND 470UH 550MA 1.1 OHM	128
B82464A4474K000 TDK EPCOS	FIXED IND 470UH 500MA 1.27 OHM	248
B82477P2683M000 TDK EPCOS	FIXED IND 68UH 1.85A 110 MOHM	345
B78108S1395J000 TDK EPCOS	FIXED IND 3.9MH 59MA 66 OHM TH	0
B82144F2474J000 TDK EPCOS	FIXED IND 470UH 600MA 2.02 OHM	4907
B82422A3680K108 TDK EPCOS	FIXED IND 68NH 480MA 210 MOHM	0
B82462A4154K000 TDK EPCOS	FIXED IND 150UH 290MA 1.76 OHM	0
B82432T1104K000 TDK EPCOS	FIXED IND 100UH 200MA 3.5 OHM	512
B82477R4362M100 TDK EPCOS	FIXED IND 3.6UH 8.5A 10 MOHM SMD	0
B82141A1273K009 TDK EPCOS	FIXED IND 27UH 315MA 1 OHM TH	0
B82422T3270K000 TDK EPCOS	FIXED IND 27NH 450MA 170 MOHM	0
B82498F3221J001 TDK EPCOS	FIXED IND 220NH 320MA 700 MOHM	0
B82133A5151M000 TDK EPCOS	FIXED IND 350UH 150MA 21 OHM TH	0
B78108E1103K009 TDK EPCOS	FIXED IND 10UH 2.25A 136 MOHM TH	6427
B82442H1474K000 TDK EPCOS	FIXED IND 470UH 170MA 5.6 OHM	477
B82559B5472A016 TDK EPCOS	FIXED IND 4.7UH 25A 2.2 MOHM SMD	407
B82472G4332M000 TDK EPCOS	FIXED IND 3.3UH 2.6A 35 MOHM SMD	768
B82442T1473K050 TDK EPCOS	FIXED IND 47UH 700MA 519 MOHM	676
B82442T1685J000 TDK EPCOS	FIXED IND 6.8MH 65MA 60.3 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