Fixed Inductors

Part Number	Description / PDF	Quantity
784775247 Würth Elektronik Midcom	FIXED IND 470UH 360MA 1.96 OHM	0
744761112C Würth Elektronik Midcom	FIXED IND 12NH 700MA 100 MOHM	2316
7447789118 Würth Elektronik Midcom	FIXED IND 18UH 1.41A 140 MOHM	246
7443340470 Würth Elektronik Midcom	FIXED IND 4.7UH 7.5A 13.5 MOHM	1599
744302007 Würth Elektronik Midcom	FIXED IND 72NH 30A 0.235 MOHM	258
744760222C Würth Elektronik Midcom	FIXED IND 220NH 400MA 1 OHM SMD	1715
7447789233 Würth Elektronik Midcom	FIXED IND 330UH 320MA 2.62 OHM	2918
744137 Würth Elektronik Midcom	FIXED IND 630UH 3.1A 175 MOHM TH	0
7447779182 Würth Elektronik Midcom	FIXED IND 82UH 840MA 430 MOHM	1590
74437529203151 Würth Elektronik Midcom	FIXED IND 150UH 9.2A 30.6 MOHM	862
744764133 Würth Elektronik Midcom	FIXED IND 33UH 70MA 5.6 OHM SMD	1066
744771002 Würth Elektronik Midcom	FIXED IND 2.2UH 10A 8 MOHM SMD	577
744062101 Würth Elektronik Midcom	FIXED IND 100UH 550MA 480 MOHM	550
7440690180 Würth Elektronik Midcom	FIXED IND 18UH 1.1A 250 MOHM SMD	0
784773156 Würth Elektronik Midcom	FIXED IND 56UH 640MA 937 MOHM	0
744773056 Würth Elektronik Midcom	FIXED IND 5.6UH 1.58A 126 MOHM	0
74408941220 Würth Elektronik Midcom	FIXED IND 22UH 650MA 549 MOHM	366
74438356047 Würth Elektronik Midcom	FIXED IND 4.7UH 2.9A 76 MOHM SMD	1135
744775147 Würth Elektronik Midcom	FIXED IND 47UH 1.17A 180 MOHM	1940
7447649168 Würth Elektronik Midcom	FIXED IND 68UH 225MA 8.45 OHM	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