Fixed Inductors

Part Number	Description / PDF	Quantity
744771233 Würth Elektronik Midcom	FIXED IND 330UH 780MA 510 MOHM	424
744731562 Würth Elektronik Midcom	FIXED IND 5.6MH 130MA 15.7 OHM	0
744325180 Würth Elektronik Midcom	FIXED IND 1.8UH 16A 3.5 MOHM SMD	0
744770122 Würth Elektronik Midcom	FIXED IND 22UH 4.1A 43 MOHM SMD	9244
744784056 Würth Elektronik Midcom	FIXED IND 5.6NH 300MA 270 MOHM	0
744772033 Würth Elektronik Midcom	FIXED IND 3.3UH 6.1A 13MOHM TH	275
831756800 Würth Elektronik Midcom	FIXED IND 6.8UH 9A 18.5 MOHM SMD	0
7447732022 Würth Elektronik Midcom	FIXED IND 2.2UH 1.71A 90 MOHM	2860
7447820036 Würth Elektronik Midcom	FIXED IND 3.6NH 310MA 250 MOHM	15000
784775212 Würth Elektronik Midcom	FIXED IND 120UH 670MA 470 MOHM	0
784773018 Würth Elektronik Midcom	FIXED IND 1.8UH 2.7A 64 MOHM SMD	0
74404052047 Würth Elektronik Midcom	FIXED IND 4.7UH 2.3A 55.9 MOHM	1594
744778215 Würth Elektronik Midcom	FIXED IND 150UH 560MA 1.27 OHM	2216
74437346082 Würth Elektronik Midcom	FIXED IND 8.2UH 3.25A 68 MOHM	123
74406042022 Würth Elektronik Midcom	FIXED IND 2.2UH 3.36A 40 MOHM	845
744053180 Würth Elektronik Midcom	FIXED IND 18UH 1.25A 110 MOHM	474
74479032 Würth Elektronik Midcom	FIXED IND 470NH 200MA 600 MOHM	7895
74408943470 Würth Elektronik Midcom	FIXED IND 47UH 800MA 351 MOHM	7737
7443550140 Würth Elektronik Midcom	FIXED IND 1.4UH 22A 2.4 MOHM SMD	388
74405020022 Würth Elektronik Midcom	FIXED IND 2.5UH 1.25A 170 MOHM	2000

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