Fixed Inductors

Part Number	Description / PDF	Quantity
74479776233 Würth Elektronik Midcom	FIXED IND 3.3UH 1.1A 130 MOHM	2390
7843340068 Würth Elektronik Midcom	FIXED IND 680NH 15.6A 4.1 MOHM	274
74404031068A Würth Elektronik Midcom	FIXED IND 6.8UH 1.29A 164 MOHM	400
744773168 Würth Elektronik Midcom	FIXED IND 68UH 560MA 1.117 OHM	1500
74404063015 Würth Elektronik Midcom	FIXED IND 1.5UH 4.58A 13 MOHM	0
744156 Würth Elektronik Midcom	FIXED IND 380UH 6.2A 70 MOHM TH	48
7443330820 Würth Elektronik Midcom	FIXED IND 8.2UH 11.5A 15 MOHM	2704
784773115 Würth Elektronik Midcom	FIXED IND 15UH 1.2A 235 MOHM SMD	0
744045150 Würth Elektronik Midcom	FIXED IND 15UH 730MA 500 MOHM	490
7447783471 Würth Elektronik Midcom	FIXED IND 470UH 370MA 2.04 OHM	0
744750420220 Würth Elektronik Midcom	FIXED IND 22UH 4.1A 36 MOHM TH	60
744760315C Würth Elektronik Midcom	FIXED IND 1.5UH 130MA 5.3 OHM	5091
784775233 Würth Elektronik Midcom	FIXED IND 330UH 430MA 1.26 OHM	125
74479276222C Würth Elektronik Midcom	FIXED IND 2.2UH 1.6A 135 MOHM	17249
74404063330 Würth Elektronik Midcom	FIXED IND 33UH 1.22A 185 MOHM	1463
744776233 Würth Elektronik Midcom	FIXED IND 330UH 520MA 1.15 OHM	250
744901033 Würth Elektronik Midcom	FIXED IND 3.3NH 380MA 400 MOHM	4758
831531000 Würth Elektronik Midcom	FIXED IND 1UH 12A 8 MOHM SMD	0
7440650033 Würth Elektronik Midcom	FIXED IND 3.3UH 5.3A 20 MOHM SMD	2932
744031470 Würth Elektronik Midcom	FIXED IND 47UH 390MA 1 OHM SMD	2934

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