Fixed Inductors

Part Number	Description / PDF	Quantity
74437334012 Würth Elektronik Midcom	FIXED IND 1.2UH 5.2A 28 MOHM SMD	0
744760233A Würth Elektronik Midcom	FIXED IND 330NH 300MA 1.65 OHM	1285
744772068 Würth Elektronik Midcom	FIXED IND 6.8UH 3.8A 25 MOHM TH	147
744758268A Würth Elektronik Midcom	FIXED IND 680NH 480MA 1.2 OHM	0
74479787210A Würth Elektronik Midcom	FIXED IND 1UH 1.7A 55 MOHM SMD	1
784774218 Würth Elektronik Midcom	FIXED IND 180UH 420MA 1.38 OHM	0
744115 Würth Elektronik Midcom	FIXED IND 200UH 2.2A 180 MOHM TH	231
744766233 Würth Elektronik Midcom	FIXED IND 330UH 85MA 14 OHM SMD	8
74405020010 Würth Elektronik Midcom	FIXED IND 1UH 1.65A 90 MOHM SMD	259
750316867 Würth Elektronik Midcom	FIXED IND 125UH 39.6 MOHM TH	41
744373460033 Würth Elektronik Midcom	FIXED IND 330NH 13A 3.9 MOHM SMD	0
7447773470 Würth Elektronik Midcom	FIXED IND 47UH 1.3A 182 MOHM SMD	558
74437368068 Würth Elektronik Midcom	FIXED IND 6.8UH 6A 23.3 MOHM SMD	1964
74408943033 Würth Elektronik Midcom	FIXED IND 3.3UH 2.6A 36 MOHM SMD	3545
744787012 Würth Elektronik Midcom	FIXED IND 1.2UH 4.85A 13 MOHM	0
744760327A Würth Elektronik Midcom	FIXED IND 2.7UH 100MA 3.5 OHM	707
744776215 Würth Elektronik Midcom	FIXED IND 150UH 810MA 470 MOHM	415
744373490082 Würth Elektronik Midcom	FIXED IND 820NH 11.25A 4.9 MOHM	0
744786033A Würth Elektronik Midcom	FIXED IND 3.3NH 600MA 150 MOHM	3555
744761227A Würth Elektronik Midcom	FIXED IND 270NH 170MA 1.8OHM SMD	2018

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