Fixed Inductors

Part Number	Description / PDF	Quantity
74408942012 Würth Elektronik Midcom	FIXED IND 1.2UH 3.2A 26 MOHM SMD	0
74404054101 Würth Elektronik Midcom	FIXED IND 100UH 700MA 560 MOHM	78
74437321100 Würth Elektronik Midcom	FIXED IND 10UH 1.2A 463 MOHM SMD	3523
744761120C Würth Elektronik Midcom	FIXED IND 20NH 700MA 120 MOHM	1102
74406042100 Würth Elektronik Midcom	FIXED IND 10UH 1.61A 133 MOHM	28
74404043470A Würth Elektronik Midcom	FIXED IND 47UH 710MA 492 MOHM	2182
744052471 Würth Elektronik Midcom	FIXED IND 470UH 140MA 5.5 OHM	123
744764015 Würth Elektronik Midcom	FIXED IND 1.5UH 370MA 850 MOHM	188
74438336022 Würth Elektronik Midcom	FIXED IND 2.2UH 2.4A 80 MOHM SMD	18
74405042010 Würth Elektronik Midcom	FIXED IND 1UH 4A 26 MOHM SMD	1280
744787068 Würth Elektronik Midcom	FIXED IND 6.8UH 3A 33 MOHM SMD	1615
7440690120 Würth Elektronik Midcom	FIXED IND 12UH 1.35A 170 MOHM	0
701014680 Würth Elektronik Midcom	FIXED IND 6.8UH 35A 1.1 MOHM SMD	115
7447797180 Würth Elektronik Midcom	FIXED IND 1.8UH 9.4A 8.4 MOHM	0
744916147 Würth Elektronik Midcom	FIXED IND 47NH 420MA 580 MOHM	100
7447706470 Würth Elektronik Midcom	FIXED IND 47UH 2.7A 72MOHM SMD	776
7447820118 Würth Elektronik Midcom	FIXED IND 18NH 170MA 810 MOHM	14974
744045210 Würth Elektronik Midcom	FIXED IND 100UH 270MA 2.5 OHM	1592
74404042331 Würth Elektronik Midcom	FIXED IND 330UH 200MA 5.3 OHM	1572
744765139GA Würth Elektronik Midcom	FIXED IND 39NH 320MA 550MOHM SMD	2710

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