Fixed Inductors

Part Number	Description / PDF	Quantity
744771006 Würth Elektronik Midcom	FIXED IND 6.8UH 6.25A 22 MOHM	500
7447706101 Würth Elektronik Midcom	FIXED IND 100UH 1.9A 140MOHM SMD	0
74438324010 Würth Elektronik Midcom	FIXED IND 1UH 2.8A 60 MOHM SMD	2241
74404064010 Würth Elektronik Midcom	FIXED IND 1UH 5.14A 11 MOHM SMD	500
744029004 Würth Elektronik Midcom	FIXED IND 4.7UH 1A 200 MOHM SMD	15832
784777022 Würth Elektronik Midcom	FIXED IND 2.2UH 2.7A 61 MOHM SMD	0
78438323010 Würth Elektronik Midcom	FIXED IND 1UH 2.5A 75 MOHM SMD	950
744042005 Würth Elektronik Midcom	FIXED IND 5.6UH 1.64A 90 MOHM	259
744025001 Würth Elektronik Midcom	FIXED IND 1.2UH 2.6A 42 MOHM SMD	2954
7443640100B Würth Elektronik Midcom	FIXED IND 1UH 56A 0.484 MOHM SMD	38
74438343012 Würth Elektronik Midcom	FIXED IND 1.2UH 1.5A 136 MOHM	0
744373965022 Würth Elektronik Midcom	FIXED IND 2.2UH 17A 4.2 MOHM SMD	1547
744373965033 Würth Elektronik Midcom	FIXED IND 3.3UH 12.2A 6.8 MOHM	627
744383130068 Würth Elektronik Midcom	FIXED IND 680NH 1.5A 126 MOHM	0
744772220 Würth Elektronik Midcom	FIXED IND 22UH 2.3A 55 MOHM TH	707
74476604 Würth Elektronik Midcom	FIXED IND 4.7UH 315MA 1 OHM SMD	0
7445420 Würth Elektronik Midcom	FIXED IND 100UH 680MA 420 MOHM	1196
744775233 Würth Elektronik Midcom	FIXED IND 330UH 430MA 1.26 OHM	332
744043680 Würth Elektronik Midcom	FIXED IND 68UH 630MA 400 MOHM	868
74404043010A Würth Elektronik Midcom	FIXED IND 1UH 4.9A 14 MOHM SMD	286

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