Fixed Inductors

Part Number	Description / PDF	Quantity
744732471 Würth Elektronik Midcom	FIXED IND 470UH 450MA 1.7 OHM TH	148
74406043331 Würth Elektronik Midcom	FIXED IND 330UH 340MA 1.864 OHM	3136
7444013119100 Würth Elektronik Midcom	FIXED IND 10UH 11A 4.8MOHM TH	10
7447820043 Würth Elektronik Midcom	FIXED IND 4.3NH 280MA 300 MOHM	14997
74431435022 Würth Elektronik Midcom	FIXED IND 220NH 31A 0.28 MOHM	1195
7443551181 Würth Elektronik Midcom	FIXED IND 18UH 7.5A 22 MOHM SMD	3161
744765143A Würth Elektronik Midcom	FIXED IND 43NH 100MA 810 MOHM	46
7447706062 Würth Elektronik Midcom	FIXED IND 6.2UH 7A 15MOHM SMD	983
7447037 Würth Elektronik Midcom	FIXED IND 360UH 400MA 450 MOHM	0
74477130W Würth Elektronik Midcom	FIXED IND 1MH 430MA 1.53 OHM SMD	0
744764027 Würth Elektronik Midcom	FIXED IND 2.7UH 290MA 1.1 OHM	1000
74405031022 Würth Elektronik Midcom	FIXED IND 2.2UH 1.75A 108 MOHM	805
7447860222 Würth Elektronik Midcom	FIXED IND 220NH 300MA 1.5 OHM	1925
7447669139 Würth Elektronik Midcom	FIXED IND 39UH 460MA 1.35 OHM	25
744040200016 Würth Elektronik Midcom	FIXED IND 160NH 3.07A 26 MOHM	1289
74437334082 Würth Elektronik Midcom	FIXED IND 8.2UH 1.9A 171 MOHM	2943
744355147 Würth Elektronik Midcom	FIXED IND 470NH 30A 0.67 MOHM	390
74454115 Würth Elektronik Midcom	FIXED IND 15UH 1.7A 85 MOHM SMD	545
7447797360 Würth Elektronik Midcom	FIXED IND 3.6UH 8.2A 12.2 MOHM	0
7447706022 Würth Elektronik Midcom	FIXED IND 2.2UH 10.2A 8.5 MOHM	935

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