Fixed Inductors

Part Number	Description / PDF	Quantity
74438324012 Würth Elektronik Midcom	FIXED IND 1.2UH 2.4A 80 MOHM SMD	500
744901122 Würth Elektronik Midcom	FIXED IND 22NH 90MA 2.6 OHM SMD	0
74456222 Würth Elektronik Midcom	FIXED IND 220UH 900MA 780 MOHM	2232
744786110 Würth Elektronik Midcom	FIXED IND 100NH 600MA 2 OHM SMD	910
7443340068 Würth Elektronik Midcom	FIXED IND 680NH 19A 3.1 MOHM SMD	0
744771003 Würth Elektronik Midcom	FIXED IND 3.5UH 9.25A 8 MOHM SMD	0
7443556082 Würth Elektronik Midcom	FIXED IND 820NH 41.5A 0.54 MOHM	131
74404064100 Würth Elektronik Midcom	FIXED IND 10UH 2.45A 48 MOHM SMD	1828
7447714471 Würth Elektronik Midcom	FIXED IND 470UH 600MA 1.1 OHM	0
7447211101 Würth Elektronik Midcom	FIXED IND 100UH 2.2A 115 MOHM TH	53
74437336068 Würth Elektronik Midcom	FIXED IND 6.8UH 2.6A 76.2 MOHM	1644
7447706221 Würth Elektronik Midcom	FIXED IND 220UH 1.25A 310 MOHM	730
744917168 Würth Elektronik Midcom	FIXED IND 68NH 600MA 330 MOHM	0
7447720472 Würth Elektronik Midcom	FIXED IND 4.7MH 210MA 9.5 OHM TH	110
784773168 Würth Elektronik Midcom	FIXED IND 68UH 560MA 1.117 OHM	0
744765062A Würth Elektronik Midcom	FIXED IND 6.2NH 760MA 83 MOHM	2021
744760339A Würth Elektronik Midcom	FIXED IND 3.9UH 200MA 2.5 OHM	479
74438333047 Würth Elektronik Midcom	FIXED IND 4.7UH 900MA 409 MOHM	536
74404052680 Würth Elektronik Midcom	FIXED IND 68UH 620MA 769 MOHM	1684
744308025 Würth Elektronik Midcom	FIXED IND 250NH 25A 0.37 MOHM	402

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