Fixed Inductors

Part Number	Description / PDF	Quantity
74477450027 Würth Elektronik Midcom	FIXED IND 270NH 8.2A 5 MOHM SMD	0
74478614 Würth Elektronik Midcom	FIXED IND 47NH 600MA 1 OHM SMD	900
784771470 Würth Elektronik Midcom	FIXED IND 47UH 2.3A 77 MOHM SMD	0
744089420056 Würth Elektronik Midcom	FIXED IND 560NH 4.1A 18.4 MOHM	0
744916121 Würth Elektronik Midcom	FIXED IND 21NH 450MA 460 MOHM	0
744762382A Würth Elektronik Midcom	FIXED IND 8.2UH 160MA 3.05 OHM	0
74477124 Würth Elektronik Midcom	FIXED IND 470UH 640MA 770 MOHM	50
7447732210 Würth Elektronik Midcom	FIXED IND 100UH 240MA 2.8 OHM	380
744912133 Würth Elektronik Midcom	FIXED IND 33NH 3A 4.8 MOHM SMD	813
7447860022 Würth Elektronik Midcom	FIXED IND 2.2NH 300MA 100 MOHM	3890
7443640680B Würth Elektronik Midcom	FIXED IND 6.8UH 47.5A 0.968 MOHM	279
744314330 Würth Elektronik Midcom	FIXED IND 3.3UH 9A 9 MOHM SMD	1333
74406032101 Würth Elektronik Midcom	FIXED IND 100UH 270MA 2.476 OHM	745
74437356010 Würth Elektronik Midcom	FIXED IND 1UH 12.5A 8.35 MOHM	0
74437321022 Würth Elektronik Midcom	FIXED IND 2.2UH 2.5A 80 MOHM SMD	3742
744373965150 Würth Elektronik Midcom	FIXED IND 15UH 6.8A 28 MOHM SMD	486
7443640470 Würth Elektronik Midcom	FIXED IND 4.7UH 30A 2.4 MOHM SMD	41
74437336012 Würth Elektronik Midcom	FIXED IND 1.2UH 6.5A 16 MOHM SMD	1921
7447785002 Würth Elektronik Midcom	FIXED IND 2.2UH 2.9A 54 MOHM SMD	564
7447669212 Würth Elektronik Midcom	FIXED IND 120UH 235MA 4.35 OHM	499

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