Fixed Inductors

Part Number	Description / PDF	Quantity
B82477R4333M100 TDK EPCOS	FIXED IND 33UH 3.55A 50 MOHM SMD	212
B82111E0000C028 TDK EPCOS	FIXED IND 680UH 200MA 14 OHM TH	0
B82422A1333K100 TDK EPCOS	FIXED IND 33UH 105MA 4.5 OHM SMD	4358
B82477R4224M100 TDK EPCOS	FIXED IND 220UH 1.45A 290 MOHM	256
B82422A1152K108 TDK EPCOS	FIXED IND 1.5UH 340MA 500 MOHM	0
B82422A1273K100 TDK EPCOS	FIXED IND 27UH 120MA 3.7 OHM SMD	1445
B82477R4103M100 TDK EPCOS	FIXED IND 10UH 6.2A 18.5 MOHM	394
B82422A1472K100 TDK EPCOS	FIXED IND 4.7UH 150MA 2.2 OHM	1622
B82144A2156J000 TDK EPCOS	FIXED IND 15MH 50MA 68 OHM TH	0
B82471A1223M000 TDK EPCOS	FIXED IND 22UH 1.11A 180 MOHM	231
B82144A2472K000 TDK EPCOS	FIXED IND 4.7UH 1.6A 160 MOHM TH	2986
B78148E1221M000 TDK EPCOS	FIXED IND 220NH 5.9A 19 MOHM TH	1779
B82141A1182K009 TDK EPCOS	FIXED IND 1.8UH 660MA 230 MOHM	0
B82496C3820J000 TDK EPCOS	FIXED IND 82NH 220MA 1.5 OHM SMD	5043
B82144B1473J000 TDK EPCOS	FIXED IND 47UH 900MA 410 MOHM TH	0
B82432C1824K000 TDK EPCOS	FIXED IND 820UH 60MA 28 OHM SMD	0
B82472P6105M000 TDK EPCOS	FIXED IND 1MH 200MA 3.85 OHM SMD	2840
B82422A3560K108 TDK EPCOS	FIXED IND 56NH 500MA 200 MOHM	0
B82559A3152A019 TDK EPCOS	FIXED IND 1.5UH 1.7 MOHM SMD	237
B82477D4202M900 TDK EPCOS	FIXED IND 2UH 6.22A 20 MOHM SMD	350

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