Fixed Inductors

Part Number	Description / PDF	Quantity
744773033 Würth Elektronik Midcom	FIXED IND 3.3UH 2A 86 MOHM SMD	10309
744314850 Würth Elektronik Midcom	FIXED IND 8.5UH 4A 32.5 MOHM SMD	3105
7447860115 Würth Elektronik Midcom	FIXED IND 15NH 300MA 320 MOHM	2380
74404043221A Würth Elektronik Midcom	FIXED IND 220UH 310MA 2.43 OHM	0
74479763168 Würth Elektronik Midcom	FIXED IND 680NH 1A 225 MOHM SMD	0
7447720470 Würth Elektronik Midcom	FIXED IND 47UH 2A 120 MOHM TH	528
7847709010 Würth Elektronik Midcom	FIXED IND 1UH 9.2A 8.5 MOHM SMD	0
744910054 Würth Elektronik Midcom	FIXED IND 5.45NH 1.6A 8 MOHM SMD	0
74451047 Würth Elektronik Midcom	FIXED IND 4.7UH 1.4A 60 MOHM SMD	10688
74404041047 Würth Elektronik Midcom	FIXED IND 4.7UH 1.55A 91 MOHM	9205
74479299222 Würth Elektronik Midcom	FIXED IND 2.2UH 2.1A 106 MOHM	3570
744777147 Würth Elektronik Midcom	FIXED IND 47UH 1.03A 260 MOHM	7717
7447713102 Würth Elektronik Midcom	FIXED IND 1MH 300MA 4.6 OHM SMD	832
74477125 Würth Elektronik Midcom	FIXED IND 560UH 620MA 860 MOHM	305
7447840082 Würth Elektronik Midcom	FIXED IND 8.2NH 300MA 330 MOHM	5948
7843340220 Würth Elektronik Midcom	FIXED IND 2.2UH 8.4A 12MOHM SMD	315
74404031150A Würth Elektronik Midcom	FIXED IND 15UH 810MA 403 MOHM	1000
7440620015 Würth Elektronik Midcom	FIXED IND 1.5UH 4.3A 18 MOHM SMD	580
7843320820 Würth Elektronik Midcom	FIXED IND 8.2UH 8.8A 15MOHM SMD	25
7443763540100 Würth Elektronik Midcom	FIXED IND 10UH 56.7A 1.2 MOHM TH	17

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