Fixed Inductors

Part Number	Description / PDF	Quantity
744917123 Würth Elektronik Midcom	FIXED IND 23NH 850MA 190 MOHM	0
784777033 Würth Elektronik Midcom	FIXED IND 3.3UH 2.5A 70 MOHM SMD	0
744732221 Würth Elektronik Midcom	FIXED IND 220UH 750MA 700 MOHM	90
744732100 Würth Elektronik Midcom	FIXED IND 10UH 4A 33 MOHM TH	0
744912182 Würth Elektronik Midcom	FIXED IND 82NH 2.5A 9.4 MOHM SMD	149
744917082 Würth Elektronik Midcom	FIXED IND 8.2NH 1.4A 54 MOHM SMD	0
74404041101 Würth Elektronik Midcom	FIXED IND 100UH 430MA 1.697 OHM	2309
74458303 Würth Elektronik Midcom	FIXED IND 3MH 500MA 3.5 OHM SMD	312
744917022 Würth Elektronik Midcom	FIXED IND 2.2NH 900MA 230 MOHM	0
744917220 Würth Elektronik Midcom	FIXED IND 200NH 280MA 2 OHM SMD	0
744766906 Würth Elektronik Midcom	FIXED IND 6.8UH 1.025A 290 MOHM	0
74404064331 Würth Elektronik Midcom	FIXED IND 330UH 510MA 1.177 OHM	4527
784773112 Würth Elektronik Midcom	FIXED IND 12UH 1.28A 210 MOHM	0
7445520 Würth Elektronik Midcom	FIXED IND 100UH 300MA 1.27 OHM	300
744760218A Würth Elektronik Midcom	FIXED IND 180NH 400MA 780 MOHM	1805
74404032010 Würth Elektronik Midcom	FIXED IND 1UH 2.2A 33 MOHM SMD	3687
74406032068 Würth Elektronik Midcom	FIXED IND 6.8UH 1.15A 153 MOHM	97
7847709068 Würth Elektronik Midcom	FIXED IND 6.8UH 5.5A 24 MOHM SMD	0
74407000047 Würth Elektronik Midcom	FIXED IND 470NH 7A 7.8 MOHM SMD	259
74457012 Würth Elektronik Midcom	FIXED IND 1.2UH 15A 4 MOHM SMD	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