Fixed Inductors

Part Number	Description / PDF	Quantity
74404054331 Würth Elektronik Midcom	FIXED IND 330UH 400MA 2.1OHM SMD	2553
744311022 Würth Elektronik Midcom	FIXED IND 220NH 21A 1.1 MOHM SMD	2689
74459247 Würth Elektronik Midcom	FIXED IND 470UH 800MA 1.08 OHM	300
74438324068 Würth Elektronik Midcom	FIXED IND 6.8UH 900MA 640 MOHM	0
744762356A Würth Elektronik Midcom	FIXED IND 5.6UH 170MA 2.6 OHM	0
744032008 Würth Elektronik Midcom	FIXED IND 8.2UH 390MA 450 MOHM	1472
744032150 Würth Elektronik Midcom	FIXED IND 15UH 270MA 1 OHM SMD	3799
74404084220 Würth Elektronik Midcom	FIXED IND 22UH 2.1A 69 MOHM SMD	3455
7447902 Würth Elektronik Midcom	FIXED IND 100NH 250MA 300 MOHM	584
744373965470 Würth Elektronik Midcom	FIXED IND 47UH 3.7A 90 MOHM SMD	377
744771122 Würth Elektronik Midcom	FIXED IND 22UH 3.37A 36 MOHM SMD	0
74431012010 Würth Elektronik Midcom	FIXED IND 100NH 37A 0.125 MOHM	300
7843330390 Würth Elektronik Midcom	FIXED IND 3.9UH 11.2A 8.7 MOHM	448
74479876222C Würth Elektronik Midcom	FIXED IND 2.2UH 1.3A 210 MOHM	260
74479298210 Würth Elektronik Midcom	FIXED IND 1UH 2.5A 54 MOHM SMD	600
74404063012 Würth Elektronik Midcom	FIXED IND 1.2UH 6.2A 11 MOHM SMD	0
78477010 Würth Elektronik Midcom	FIXED IND 1UH 8.3A 9 MOHM SMD	0
7447840215 Würth Elektronik Midcom	FIXED IND 150NH 140MA 2.99 OHM	19999
744760282A Würth Elektronik Midcom	FIXED IND 820NH 300MA 1.5 OHM	3322
7447786001 Würth Elektronik Midcom	FIXED IND 1UH 5A 34 MOHM SMD	1982

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