Fixed Inductors

Part Number	Description / PDF	Quantity
B82422A1333J100 TDK EPCOS	FIXED IND 33UH 105MA 4.5 OHM SMD	0
B78148E1683J009 TDK EPCOS	FIXED IND 68UH 780MA 105 MOHM TH	0
B82498F3681J001 TDK EPCOS	FIXED IND 680NH 190MA 1.7 OHM	0
B82432C1224K000 TDK EPCOS	FIXED IND 220UH 115MA 7.5 OHM	32
B82422A1104K100 TDK EPCOS	FIXED IND 100UH 65MA 11.5 OHM	503
B82498F3121G000 TDK EPCOS	FIXED IND 120NH 440MA 310 MOHM	0
B82472P6224M000 TDK EPCOS	FIXED IND 220UH 430MA 880 MOHM	867
B82464P4821M000 TDK EPCOS	FIXED IND 820NH 7.5A 7 MOHM SMD	750
B82477P4472M000 TDK EPCOS	FIXED IND 4.7UH 7.3A 12 MOHM SMD	104
B82141A1103K000 TDK EPCOS	FIXED IND 10UH 410MA 600 MOHM TH	3706
B82144B1474J000 TDK EPCOS	FIXED IND 470UH 400MA 2.2 OHM TH	0
B82111B0000C020 TDK EPCOS	FIXED IND 20UH 3A 54 MOHM TH	512
B82422A1393J100 TDK EPCOS	FIXED IND 39UH 90MA 6.3 OHM SMD	0
B82442H1105K000 TDK EPCOS	FIXED IND 1MH 120MA 12 OHM SMD	39
B78108S1335J000 TDK EPCOS	FIXED IND 3.3MH 62MA 59.5 OHM TH	9212
B82498F3220G001 TDK EPCOS	FIXED IND 22NH 700MA 80 MOHM SMD	0
B82472G6104M000 TDK EPCOS	FIXED IND 100UH 670MA 390 MOHM	0
B82422A3151K108 TDK EPCOS	FIXED IND 150NH 390MA 330 MOHM	0
B82464P4103M000 TDK EPCOS	FIXED IND 10UH 3.4A 30 MOHM SMD	792
B82111E0000C020 TDK EPCOS	FIXED IND 7UH 6A 20 MOHM TH	1344

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