Fixed Inductors

Part Number	Description / PDF	Quantity
B78108S1184J009 TDK EPCOS	FIXED IND 180UH 270MA 3 OHM TH	0
B82422T1102K008 TDK EPCOS	FIXED IND 1UH 400MA 600 MOHM SMD	0
B82500C0000A010 TDK EPCOS	FIXED IND 120UH 2A 150 MOHM TH	165
B82141A1272K000 TDK EPCOS	FIXED IND 2.7UH 610MA 270 MOHM	0
B82442A1472K000 TDK EPCOS	FIXED IND 4.7UH 950MA 88 MOHM	0
B82464P4333M000 TDK EPCOS	FIXED IND 33UH 1.85A 75 MOHM SMD	725
B82442T1123K050 TDK EPCOS	FIXED IND 12UH 1.38A 141 MOHM	0
B82141A1472J000 TDK EPCOS	FIXED IND 4.7UH 530MA 360 MOHM	0
B82422T1223J000 TDK EPCOS	FIXED IND 22UH 110MA 3.5 OHM SMD	0
B82131A5402M000 TDK EPCOS	FIXED IND 1UH 4A 14 MOHM TH	3083
B82422A3680J100 TDK EPCOS	FIXED IND 68NH 480MA 210 MOHM	0
B78148E1101M000 TDK EPCOS	FIXED IND 100NH 7.3A 15 MOHM TH	950
B78108T1822K009 TDK EPCOS	FIXED IND 8.2UH 240MA 1.6 OHM TH	0
B82473M1683K000 TDK EPCOS	FIXED IND 68UH 850MA 280 MOHM	0
B82477R4562M100 TDK EPCOS	FIXED IND 5.6UH 7.6A 11.5 MOHM	0
B82422A3391K100 TDK EPCOS	FIXED IND 390NH 190MA 1.4 OHM	0
B82144B1682K000 TDK EPCOS	FIXED IND 6.8UH 1.6A 150 MOHM TH	0
B82422T1102J000 TDK EPCOS	FIXED IND 1UH 400MA 600 MOHM SMD	5954
B82422H1684K000 TDK EPCOS	FIXED IND 680UH 61MA 31 OHM SMD	24029
B82442H1224K000 TDK EPCOS	FIXED IND 220UH 240MA 2.72 OHM	4882

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