Fixed Inductors

Part Number	Description / PDF	Quantity
744134 Würth Elektronik Midcom	FIXED IND 92UH 5.4A 50 MOHM TH	0
744089430022 Würth Elektronik Midcom	FIXED IND 220NH 5A 14 MOHM SMD	0
74457168 Würth Elektronik Midcom	FIXED IND 68UH 2.4A 134 MOHM SMD	13
78438335150 Würth Elektronik Midcom	FIXED IND 15UH 650MA 830 MOHM	0
74437346022 Würth Elektronik Midcom	FIXED IND 2.2UH 6.5A 20 MOHM SMD	511
7443091120 Würth Elektronik Midcom	FIXED IND 1.2UH 34A 0.42 MOHM	404
744762227A Würth Elektronik Midcom	FIXED IND 270NH 600MA 750 MOHM	665
74404042033 Würth Elektronik Midcom	FIXED IND 3.3UH 2A 55 MOHM SMD	8180
744750560100 Würth Elektronik Midcom	FIXED IND 10UH 11.4A 6.8 MOHM	73
74437324068 Würth Elektronik Midcom	FIXED IND 6.8UH 1.75A 172 MOHM	2014
74404024330 Würth Elektronik Midcom	FIXED IND 33UH 440MA 1.53 OHM	0
74437349012 Würth Elektronik Midcom	FIXED IND 1.2UH 9A 7.5 MOHM SMD	837
74476406 Würth Elektronik Midcom	FIXED IND 6.8UH 180MA 1.8 OHM	0
7443310068 Würth Elektronik Midcom	FIXED IND 680NH 23A 1.85 MOHM	0
7447462330 Würth Elektronik Midcom	FIXED IND 33UH 1.4A 220 MOHM TH	90
74477002 Würth Elektronik Midcom	FIXED IND 2.4UH 10.1A 12 MOHM	12
7445820 Würth Elektronik Midcom	FIXED IND 100UH 1.8A 190 MOHM	407
74404054680 Würth Elektronik Midcom	FIXED IND 68UH 800MA 400 MOHM	1635
744025100 Würth Elektronik Midcom	FIXED IND 10UH 1A 190 MOHM SMD	33493
74437377010 Würth Elektronik Midcom	FIXED IND 1UH 15A 3.5 MOHM SMD	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