Fixed Inductors

Part Number	Description / PDF	Quantity
B82422A1102K108 TDK EPCOS	FIXED IND 1UH 380MA 340 MOHM SMD	0
B82498F3120J001 TDK EPCOS	FIXED IND 12NH 700MA 90 MOHM SMD	0
B78108E1104J000 TDK EPCOS	FIXED IND 100UH 640MA 1.45 OHM	1845
B82476B1224M100 TDK EPCOS	FIXED IND 220UH 880MA 530 MOHM	1362
B82442H1563K000 TDK EPCOS	FIXED IND 56UH 430MA 800 MOHM	0
B82559B4332A027 TDK EPCOS	FIXED IND 3.3UH 42.5A 0.88 MOHM	310
B78108S1184J000 TDK EPCOS	FIXED IND 180UH 270MA 3 OHM TH	1396
B82498F1472J000 TDK EPCOS	FIXED IND 4.7UH 90MA 3.8 OHM SMD	4934
B82442H1823J000 TDK EPCOS	FIXED IND 82UH 380MA 1.12 OHM	0
B82477G2153M000 TDK EPCOS	FIXED IND 15UH 3.3A 30 MOHM SMD	0
B82477G2473M000 TDK EPCOS	FIXED IND 47UH 1.8A 75 MOHM SMD	629
B82111B0000C024 TDK EPCOS	FIXED IND 25UH 3A 46 MOHM TH	982
B82422T3330J000 TDK EPCOS	FIXED IND 33NH 450MA 180 MOHM	0
B82144B1334J000 TDK EPCOS	FIXED IND 330UH 500MA 1.7 OHM TH	0
B82442T1683K050 TDK EPCOS	FIXED IND 68UH 570MA 781 MOHM	0
B82422A1102J108 TDK EPCOS	FIXED IND 1UH 380MA 340 MOHM SMD	0
B82144F2394J000 TDK EPCOS	FIXED IND 390UH 650MA 1.72 OHM	0
B82498F3181G001 TDK EPCOS	FIXED IND 180NH 340MA 530 MOHM	0
B78148E1153K000 TDK EPCOS	FIXED IND 15UH 1.6A 230 MOHM TH	1593
B82472D6682M000 TDK EPCOS	FIXED IND 6.8UH 2.75A 75 MOHM	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